Turpin has a tough exterior, but works well with his fellow Metropolis police and tries to help save people.
A young Lieutenant Dan Turpin, despite having a good wife and children, had begun to fall in with bad cops, who conspired to kill certain escaped convicts, as well as detective John Jones, who was trying to stop the conspiracy. Turpin met young Clark Kent, who had infiltrated the police department. Kent convinced him to come clean and become an honest cop. Turpin has maintained his integrity ever since. (Smallville, season 8)
Turpin served for many years alongside Maggie Sawyer. The two served on the metropolis Special Crimes Unit. He would later come to realize that he was in love with Maggie and proposed to her. However, Maggie was already in a relationship with a woman, Toby Raynes, and she turned him down. Embarrassed, Dan decided to resign, but Maggie stopped him from doing so. The two continued as partners and friends.
Most recently, during Final Crisis, Turpin was captured by followers of Darkseid. Turpin was then restrained and forced to become host to Darkseid. Although Turpin was able to resist the mental takeover for some time, it was not enough, and he became Darkseid.