Siobhan McDougal was the first-born child of Garrett McDougal, the patriarch of an old Gaelic clan that has occupied an island midway between Scotland and Ireland for a thousand generations. On that island is Castle Broen, where first-born McDougals undergo a ritual to prove themselves worthy to lead the clan. When Siobhan was young, she traveled the world, only returning to Castle Broen when she heard of her father's death. Her uncle Seamus determined that no woman would lead the clan and intended her brother Bevan to become the new patriarch. She went ahead with the family ritual by herself, which involved calling on supernatural forces for power. She was interrupted by Bevan, and the distraction proved disastrous as she was dragged away into an infernal netherworld. An entity called "the Crone" granted her powers and the ability to return to Earth as the Silver Banshee, but demanded payment in the form of an occult book that belonged to her father. She found that her father's book collection had been shipped off for sale in the United States. Her quest brought her to Metropolis. Killing anyone that stood in the way of her search attracted the attention of Superman. Unable to defeat Superman, she chose to retreat and continue her mission at a later date.
Silver Banshee returned to Metropolis twice more, but was halted both times by Superman. It was Batman who finally found the book among some stolen goods in Gotham City. Superman brought the book to Castle Broen where he was confronted by Silver Banshee. The Crone appeared at the castle, and after an enigmatic warning to Superman, she dragged the Banshee, Bevan, and Seamus off to her netherworld.
In Leesburg, Supergirl rescued Silver Banshee from Satanus' Netherworld when the chaos flow brought the river Styx to the town. Silver Banshee was left in a confused state, eventually going back to her psychotic persona and using Supergirl's friend Mattie as a host while rampaging on the streets. Mattie and Silver Banshee thus proceeded to nearby Schnaffenburg where Mattie tried to get revenge on Gerald McFee, who killed her brother during Final Night while in thrall to Gorilla Grodd. Supergirl calmed Silver Banshee, separating Mattie from her, which led to Silver Banshee temporarily vanishing.
Inspector Henderson with other police officers break into an apartment, but it explodes and then they find a corpse covered in runes. Kara meets with Inspector Henderson, who's following a case his old mentor was never able to close, and thinks it has to do with items Silver Banshee needs to lift her curse. Inspector Henderson finds his mentor had the item, but it imbeds itself in Inspector Henderson's hand, allowing Silver Banshee to track him. Silver Banshee shows up and fights Supergirl, but Supergirl opens a package from Henderson and becomes possessed by a Banshee hybrid. Banshee-Supergirl and the Silver Banshee battle each other as events are recapped. Supergirl tells Silver Banshee they hid the artifacts in people, in order to keep them hidden from her. Apparently all the items were hidden not as a curse, but as a test for prospective clan leaders. Henderson punches Banshee-Supergirl, which is effective because of the artifact in his hand. Supergirl tries to exorcise the spirits possessing her but fails. Henderson realizes the spirits are tied to the artifacts and can be used against them. He then stabs his hand and breaking Supergirl free from her spirits. Silver Banshee then uses her wails to disperse the spirits. She finally uses magic to remove the artifacts from Henderson's hand and lets him know she is indebted to him.
In other media
- In Justice League Unlimited, Silver Banshee accompanied Metallo to Skartaris to retrieve a large chunk of Kryptonite in the episode "Chaos At Earth's Core". She is captured by Green Lantern after he uses his power ring to gag her. She escaped soon after being captured. Kim Mai Guest is credited for voicing Silver Banshee even though she has no identifiable dialogue. Silver Banshee is shown to be a member of the Secret Society shown on Justice League Unlimited finale, "Alive". As she is seen fighting on Grodd's side during his mutiny against Lex Luthor, but is not shown among those frozen by Killer Frost, it is likely she was killed during the mutiny.
- Silver Banshee appeared in the 15th episode of the 9th season of Smallville, titled "Escape". She was played by Odessa Rae. This version is a deceased Gaelic heroine, who was cursed and placed in the underworld. Just like her recent appearances on the comics, this version needs to possess a host. Her abilities are sonic scream, superhuman strength, stamina and durability. When she utilizes her powers, her retina glows white.
- A character named "Scream Queen" appears in the Batman: The Brave and the Bold television series. She is based on Silver Banshee, and her outward hooded appearance is similar to Raven.
- Italia Ricci portrays Siobhan Smythe in a recurring role on the TV series Supergirl. She starts out as Cat Grant's second assistant and Kara's rival, but eventually becomes the Silver Banshee and allies with Livewire to battle Supergirl and The Flash.
- Silver Banshee appears in the animated movie Superman/Batman: Public Enemies. She is one of the many supervillains that wants to collect the $1 billion bounty that President Lex Luthor placed on Superman. She is defeated when Superman takes her to the upper limits of the atmosphere where she cannot breathe, and while she is unconscious, Batman puts a device on her that would nullify her power by turning it against her.
- She, along with Parasite and Brainiac, were considered as the three main villains in Superman Reborn, but the film was canceled before it began production.