Clark Kent is Superman's secret identity.
Clark Kent's name is a combination of the names of actors, Clark Gable and Kent Taylor. His physical design is believed to be modeled after science fiction fan Walter Dennis, who sent Joe Shuster his photograph. Through the popularity of his Superman alter ego, the personality, concept, and name of Clark Kent have become ingrained in popular culture as well, becoming synonymous with secret identities and innocuous fronts for ulterior motives and activities.
First written in the earliest Superman comics, Clark Kent's primary purpose was to fulfill the perceived dramatic requirement that a costumed superhero cannot stay on-duty twenty-four hours a day, or throughout the entirety of a comic book series. As such, Kent acted as little more than a front for Superman's activities. Although his name and history were taken from his early life with his adoptive Earth parents, everything about Kent was staged for the benefit of his alternate identity he acquired a job as a reporter for the Daily Planet for the convenience of receiving late-breaking news before the general public, providing an excuse for being present at crime scenes and having an occupation where his whereabouts do not have to be strictly accounted for as long as he makes his story deadlines. However, in order to draw attention away from the correlation between Kent and Superman, Clark Kent adopted a largely passive and introverted personality, applying conservative mannerisms, a higher-pitched voice, and a slight slouch. This personality is typically described as "mild-mannered," perhaps most famously by the opening narration of Max Fleischer's Superman animated theatrical shorts. These traits extended into Kent's wardrobe, which typically consists of a softly-colored business suit, a red necktie, black-rimmed glasses, combed-back hair and, occasionally, a fedora.
Kent wears his Superman costume underneath his street clothes, which lends itself to easy transference between the two personalities. However, the purpose of this convention outside of fiction is largely dramatic, allowing Kent to rip open his shirt and reveal the familiar "S" insignia when called into action. When in action, Superman usually stores his Clark Kent clothing shrunken down inside a secret pouch hidden inside of his cape, though some stories have shown him leaving his clothes in some covert location (usually places like phone booths) for later retrieval. In addition with the Pre-Crisis comic book title, Superman Family, Kent is featured in a series of stories called "The Private Life of Clark Kent," where he solves problems subtly without changing into Superman.
In the wake of John Byrne's The Man of Steel reboot of Superman continuity, many traditional aspects of Clark Kent were dropped in favor of giving him a more aggressive and extroverted personality, including such aspects as making Kent a top football player in high school, along with being a successful author. Recently, some aspects of this change have been dropped, in favor of bringing back elements of the earlier, "mild-mannered" version of Kent. Feeling that Clark is the real person and that Clark is not afraid to be himself in his civilian identity, John Byrne has stated in interviews that he took inspiration for this portrayal from the George Reeves version of Superman.
Adopted by Jonathan Kent and his wife Martha Kent of Smallville, USA, Clark (and thus Superman) was raised with the values of a typical small, rural American town. Most continuities state that the Kents had been unable to have biological children. In the traditional versions of his origin, after the Kents retrieved Clark from his rocket, they brought him to the Smallville Orphanage, and returned a few days later to formally adopt the orphan, giving him as a first name Martha's maiden name, "Clark." In John Byrne's 1986 origin version The Man of Steel, instead of an orphanage, the Kents passed Clark off as their biologically-born son (after a lengthy months-long series of snowstorms trapped them on their farm).
In the Silver Age comics continuity, Clark gained superpowers upon landing on Earth, and gradually learned to master them, adopting the superhero identity of Superboy at the age of eight. He subsequently developed Clark's timid demeanor as a means of ensuring that no one would suspect any connection between the two alter-egos.
In Metropolis, Superman (as Clark Kent) works as a reporter at the Planet, "a great metropolitan newspaper" which allows him to keep track of ongoing events where he might be of help. Largely working on his own, his identity is easily kept secret. He sees his job as a journalist as an extension of his Superman responsibilities, bringing truth to the forefront and fighting for the little man.  Fellow reporter Lois Lane became the object of Clark's/Superman's romantic affection. Lois' affection for Superman and her rejection of Clark's clumsy advances have been a recurring theme in Superman comics, television, and movies.
Secret identity security
Various reasons over the decades have been offered for why people haven't suspected Superman and Clark Kent of being one and the same. The most common offered is simply that, despite their physical resemblance, Superman and Clark are perceived as too different in mannerisms and personality to be the same individual. In the 1970s, one suggestion was that the lenses of Clark Kent's glasses (made of Kryptonian materials) constantly amplified a low-level super-hypnosis power, thereby creating the illusion of others viewing Clark Kent as a weak and frailer being; however, this reason was abandoned almost as quickly as it was introduced, since it had various flaws (such as stories where Batman would disguise himself as Clark Kent, among others).
Another reason given in the late 1980s was the public simply does not know that Superman has a secret identity, considering he does not wear a mask, which implies to most that he has nothing to hide. As an added precaution, Superman would vibrate his face (like Jay Garrick, the Golden-Age Flash), slightly so that photographs would only show his features as a blur, thus preventing the danger of photographs of both identities being reliably compared. However, more recent stories showing Superman being photographed have tended to ignore this factor. The 2004 series Superman: Birthright also explained that Superman's eyes are an unnaturally vivid shade of blue. Clark's glasses diffuse the color and make his eyes appear more human in that identity. A new element that has shown up recently is the fact that most people only know of Clark as a name in a byline, and only see Superman from a distance, if they see him at all. As most people don't spend a lot of time with both Clark Kent and Superman the similar appearance doesn't come up.
Traditionally, Lois Lane (and sometimes others) would often suspect Superman of truly being Clark Kent (and vice-versa), though more recent comics often feature the general public assuming that Superman doesn't have a secret identity. In Superman vol. 2, #2 (1987), for example, a super-computer constructed by Lex Luthor calculated Superman's true identity, but Lex dismissed the idea because he could not believe that someone so powerful would want another weaker identity. In modern comic continuity as of 2006, Lois Lane never suspected the dual identity, beyond one isolated question, before Clark revealed it to her. She had visited the Kent farm, but was told there that Superman was "brought up" alongside Clark like a brother.
Some fans have noted that in order for the disguise to be credible, Clark has to be at least as skilled an actor as Christopher Reeve. The actor's portrayal of Clark in the feature film series was praised for making the disguise's effectiveness credible to audiences. In his book Still Me, Reeve says he based Clark Kent on Cary Grant's nerdy character in Bringing up Baby.
According to the 2004 limited series Superman: Birthright (which retells Superman's origin), young Clark Kent studies the Meisner technique so that he can seamlessly move between his Clark and Superman personas. As Clark, he drops his head, lowers his shoulders, bends his back forward a little bit and talks in a lighter tone, while as Superman, he stands straight and talks in a deeper tone. In the 2006 feature film, Brandon Routh's performance echoed Reeve's.
Actor George Reeves in the 1950s live-action television series Adventures of Superman brought a naturalistic approach to the dual role, perhaps reasoning that if Clark were too much of a milquetoast, he would not do well in the tough world of investigative journalism, particularly with an aggressive editor like Perry White. Reeves played Clark as moderately assertive, often taking charge in dangerous or risky situations and unafraid to take reasonable risks. This may have been an inspiration for the 1980s reboot of the Kent half of the Superman character.
Actor Dean Cain's approach in the 1990s series Lois & Clark: The New Adventures of Superman was to have Clark as a normal everyday guy demonstrating touches of clumsiness (e.g., pretending to burn his mouth on coffee) but still a highly skilled journalist. His Superman, by contrast, was very much the model of the classic hero who stood up straight and spoke in a more formal and authoritative voice. In the episode "Tempus Fugitive", the time-traveller Tempus mocks Lois (Teri Hatcher), saying that future historians laugh at her for being "fooled by a pair of glasses".
Identity change as a plot device and stylistic choice
When crises arise, Clark quickly changes into Superman. Originally during his appearances in Action Comics and later in his own magazine, the Man of Steel would strip to his costume and stand revealed as Superman, often with the transformation having already been completed. But within a short time, Joe Shuster and his ghost artists began depicting Clark Kent ripping open his shirt to reveal the "S" insignia on his chest -- an image which became so iconic that other superheroes, during the Golden Age and later periods, would copy the same type of change during transformations (only Spider-Man, through his appearances in comics and Sam Raimi's films, has come remotely close to matching Superman in terms of being connected with the famed shirt-rip shot). In the Fleischer animated series of theatrical cartoons released by Paramount, the mild-mannered reporter often ducked into a telephone booth or stock room to make the transformation. Since the shorts were produced during the rise of film noir in cinema, the change was usually represented as a stylized sequence: Clark Kent's silhouette is clearly seen behind a closed door's pebble glass window (or a shadow thrown across a wall) as he strips to his Superman costume. Then, the superhero emerges having transformed from his meek disguise to his true self. In the comic books and in the George Reeves television series, he favors the Daily Planet's store room (the heroic change between identities within the store room is almost always seen in the comics, but never viewed in the Reeves series). The CBS Saturday morning series The New Adventures of Superman produced by Filmation Studios -- as well as The Adventures of Superboy from the same animation house -- featured the iconic "shirt rip" to reveal the "S," or Clark Kent removing his unbuttoned white dress shirt in a secluded spot, usually thanks to stock animation which was re-used over dozens of episodes, to reveal his costume underneath while uttering his famed "This is a job for Superman!" line. In Lois & Clark: The New Adventures of Superman, Clark's usual method of changing was to either "suddenly" remember something urgent that required his immediate attention or leave the room/area under the pretense of contacting a source, summoning the police, heading to a breaking story's location, etc. Clark also developed a method of rapidly spinning into his costume at super speed which became a trademark change, especially during the third and fourth seasons of the series, and extremely popular with the show's fans. As a dramatic plot device, Clark often has to quickly improvise in order to find a way to change unnoticed. For example, in the first Christopher Reeve film, Superman: The Movie (1978), Kent, unable to use a newer, open-kiosk pay phone (and getting a nice laugh from the theater audience), runs down the street and rips his shirt to reveal his costume underneath. He quickly enters a revolving door, spinning through it at incredible speed while changing clothes. Thus made invisible, he appears to have entered the building as Clark Kent and exited seconds later as Superman.
Which is the real "identity"?
A relatively recent debate is which of the two identities (Superman or Clark Kent) is the real person and which is the faςade. Pre-Crisis interpretations of Superman very much assumed that Clark Kent was the "mask" and Kal-El the person (in the classic story Superman: Whatever Happened to the Man of Tomorrow?, when Superman's dual life is revealed, he completely abandons his Clark Kent persona). With John Byrne's more assertive revamp of Clark Kent as well as Superman's greater grounding in Earth culture and humanity (as opposed to the everpresent Kryptonian heritage of the Pre-Crisis version), Superman is considered the "mask" and Clark the person. This is made explicit by Clark himself in Superman vol. 2, #53, when following his revelation to Lois of his role as Superman (Action Comics #662), he states: "I'm Clark, the man you love. Superman is the creation -- you named me, Lois." In pre-Crisis Continuity, Kal-El was already a toddler before leaving Krypton, and retained memories of that childhood that later resurfaced; in post-Crisis continuity, he was sent to Earth pre-natally in a "birthing matrix" (more recently retconned as an infant) and raised entirely by the Kents. As a result of their rearing, Kal-El has grown to think of himself as Clark Kent, and in fact was completely unaware of his alien heritage until he was well into adulthood. Although the morals instilled in him by the Kents have motivated Kal-El to use his abilities to help others, he developed the Superman persona to protect his Clark Kent identity. Thus he is Kal-El, who thinks of himself as Clark Kent, wearing a Superman "mask".
Many fans and Superman scholars believe there to actually be three interpretations. There is firstly who Clark is when he is around trusted friends and family, particularly whilst on the farm with Martha, or in moments alone with Lois. He is a regular guy, brave, and moral. He then wears two other masks: that of the heroic Superman, and that of the bumbling and goofy Clark Kent who works at The Daily Planet. It should be noted that "bumbling" Clark is an act, but some fans dislike the portrayal of Clark as bumbling and goofy, as they feel it marginalizes his importance to the character. This idea has appeared in comics and various adaptations. In a pre-Crisis story by Alan Moore in DC Comics Presents #85. A sick Kal-El has hallucinations of both the Superman costume and Clark's suit, both offering advice from different viewpoints, and insists that neither of them are real. Rather the reverse relationship exists between Bruce Wayne and the Batman, in whose case Bruce Wayne is the fiction and Batman is the reality.
Other concepts have become the current accepted canon in most modern versions of the Superman myth (for example, in the DC animated universe Superman cartoon episode "The Late Mr. Kent", wherein Clark Kent is presumed dead, Superman expresses frustration at the idea of not being Clark and having to be someone else instead, because, in his words: "I am Clark Kent. I need to be Clark. I'd go crazy if I'd have to be Superman all the time.")
In other media
Clark Kent's character is given heavier emphasis than his superheroic alter-ego in the 1990s series Lois & Clark: The New Adventures of Superman and the 2000s series Smallville, where Clark has not yet adopted the identity of Superman. In Lois & Clark, Lois discovers his identity and angrily states that "you're Superman", but Clark says, "No, Lois. Superman is what I can do. Clark is who I am."
In 1978 the first of four Superman films was made in which Clark Kent and Superman were portrayed by Christopher Reeve. In these movies, to further separate Clark Kent from Superman, Reeve made Clark more goofy and as usual Clark had glasses with no "S" curl in his hair. In Superman Returns, Brandon Routh takes up the mantle as Superman and Clark Kent in which his Clark Kent is very reminiscent of Christopher Reeve's. Both Richard Donner and Bryan Singer have stated that Clark Kent is intended to be the disguise. However, while the Donner films tend to imply that Superman is the actual persona, Singer stated at the 2006 Comicon that he favored the three-persona concept, stating that there was Kal-El (the last son of Krypton, raised by the Kents), the bumbling Metropolis Clark and Superman.
In the ongoing TV series Smallville, Clark Kent (Tom Welling) is initially portrayed as being a shy teenager who is very unsure of himself. At the start of the series he is unaware of his origins or of any future powers he will develop. Initially he is shown as having a close friendship with Pete Ross (Sam Jones III) and original character Chloe Sullivan (Allison Mack), with whom he works on the school's newspaper: The Torch. Also, in a twist on the accepted canon, he is portrayed as having a long-term crush on "girl next door" Lana Lang (Kristin Kreuk); much of the show's premise revolves around the permutations of their relationship. He also develops a close friendship with Lex Luthor (Michael Rosenbaum) after saving his life.
During the show's second season, viewers were first introduced to another side of Clark that appeared when he came into close contact with red kryptonite. This version, who referred to himself as Kal, is often quantified as being Clark without inhibitions: he becomes less concerned with those around him and tends to act on impulse for instant gratification. He appears to act in an increasingly amoral way that correlates to the amount of time that he has been exposed to the red kryptonite. Kal is often used as a plot device, like amnesia, by the writers to explore thoughts and feelings Clark might not otherwise express due to his inhibitions. He also tends to dress in darker colours like black and green, in contrast to the red and blue staple of Clark's normal wardrobe, to symbolise the change in character.
It was also during the second season that Clark first came into contact with an AI acting as a proxy to his biological father, Jor-El (Terence Stamp). This marked the start of a largely antagonistic relationship between them: the AI, generally referred to simply as Jor-El, strongly suggested to Clark that he was sent to Earth to conquer. This prompted Clark, by and large, to reject his "destiny" as dictated to him by Jor-El from then on. Jor-El is frequently contrasted with Jonathan Kent (John Schneider), Clark's adoptive father, who takes a diametric opinion on what Clark's destiny is, and what is best for him. However, when Clark spends three months in Metropolis as Kal, Jonathan and Jor-El work together to bring him back to Smallville. Christopher Reeve played Dr. Virgil Swann during this season, a character who provides Clark with more information about his origins.
Season three is somewhat pre-occupied by Clark's revelations about his Kryptonian heritage. Clark also meets Perry White (Michael McKean) for the first time during season three, as a down-and-out tabloid journalist. During this season, Pete Ross, as a result of circumstances that evolved partly as a result of his finding out about Clark's secret leaves Smallville to live in Wichita, Kansas. This sparked a shift in relationships around Clark. At the end of this season, Clark is approached by a girl named Kara, in a nod to Supergirl, who displayed Kryptonian-esque powers and claimed to be from Krypton. She is later revealed to be a human called Lindsey who was granted these powers by Jor-El.
In the season finale, Clark is 'reprogrammed' by Jor-El into an automaton who goes by "Kal-El", his Kryptonian name. It is surmised that even with Kryptonian tutleage, Kal-El was made more of soldier type purposely. This was presumbly necessary as Clark had resisted the advice of Jor-El. It is during his time as Kal-El that he first flies. Brigette Crosby (Margot Kidder) reveals that he had come into his full power as a result of accepting his Kryptonian destiny. When Clark is later restored (using black kryptonite), he can no longer fly and it is implied that this is because he has not yet accepted his destiny as Clark Kent. It was also during the season opener of season four that the character of Lois Lane (Erica Durance) is first introduced, initially to Kal-El, and later to Clark.
Season four revolved around a plot concerning a set of Kryptonian crystals that contained the knowledge of the universe. When Clark collected them, they formed a "mother crystal" and he was transported from the show's Kawatche caves to the Arctic where the crystal forms his Fortress of Solitude. Chloe also discovered his secret during season four, having had it revealed to her by Clark's girlfriend, Alicia Baker (Sarah Carter).
Season five saw the introduction of Milton Fine as a lecturer at Clark's college, initially playing the role of mentor and later revealed to be the comic book villain Brainiac (Brain InterActive Construct) who ends up forging a tenuous alliance with Lex Luthor. This season also saw what is purported to be the final breakup of Clark and Lana's romantic relationship, with Lana moving towards a romantic relationship with Lex towards the end of the season. Clark learns about the existence of the Phantom Zone and also about the Kryptonian villain Zod who escapes from the Phantom Zone to possess Lex Luthor in the season finale.
Season six opens on Clark inside the Phantom Zone, where he is powerless. He forges a relationship with fellow Kryptonian prisoner, Raya, who claims to have been Jor-El's lab assistant on Krypton. She teaches him more about what his father was like in real life and frees him from the Phantom Zone, along with a crystal with which he can defeat Zod and other Phantom Zone-escapees. She continues in this capacity when she escapes from the Phantom Zone herself later on. Jor-El is no longer considered without compassion, now simply acting as he sees best in the dire circumstances.
Smallville shows a steady development of Clark's powers over time. When the show begins, he already possesses some of his exceptional strength and speed, but seems unaware that he can resist major damage until the moment in the pilot when he his hit by a car and suffers no injuries. During the course of the series, Clark comes into many of his iconic powers during the course of the show, including heat vision, X-ray vision, super-hearing and, most recently, super-breath. All of his powers show a steady increase in intensity from season to season, with his invulnerability extending to being bulletproof by the end of the first season, for example. It also tracks changes in relationships and Clark's own characteristics that lead him eventually to taking up the mantle of Superman.
- In the modern age continuity of comics, Clark Kent's favorite movie is To Kill a Mockingbird. (Superman #s 67 and 81)
- Clark Kent is 6' 3", is in his mid-thirties, and weighs 225 pounds. Superman, in the 1978 movie, says that he himself is 6' 4", "over 21", and weighs 225.
- According the DC comics official guide to Superman, Clark enjoys peanut butter and jelly sandwiches, football games, and the smell of Kansas in the springtime. In addition, Clark also enjoys the simplicity of his life as a reporter.
- Clark Kent is a self-described "blue jeans and T-shirt kind of guy".
- Clark Kent's favorite baseball team is the Metropolis Monarchs.
- Clark Kent's favorite football team is the Metropolis Sharks.