Nancy was kidnapped by a child rapist and the son of Senator Roark, Roark Junior when she was 11 years old. She would soon be rescued by Detective John Hartigan. However, Hartigan was shot in the back by his partner Bob and was framed for raping Nancy. Hartigan was hospitalized and was forced to be convicted of crimes he did not commit. Nancy tried to testify against Roark Junior, but the police denied it because they assumed she was still in shock after her "rape." Nancy visits Hartigan at the hospital where he tells her to stop visiting him and trying to contact him because she could get killed for it. Nancy tells Hartigan that she will continue to write to him and sign under the name "Cordelia." While growing up, Nancy was roughed up by some frat boys. However, Marv was there to save Nancy, and the two have grown close together.
Nancy continues to write to Hartigan for years, until one day, Hartigan realizes that her letters stopped coming. However, a letter arrives later and there was a finger inside it. Fearing for Nancy's life, Hartigan confesses to all his "crimes" to get on early parole. After he gets out, he goes looking for Nancy and discovers her stripper career at Kadie's bar. When Nancy recognized Hartigan, she jumps off the stage and kisses him. Hartigan convinces Nancy that they are in danger and they quickly leave the bar. While in the car, the two realize that they are being chased by a yellow man that is shooting at them. Hartigan would shoot him and cause the yellow man to crash. They stop at a motel to rest, and Nancy would confess her love to Hartigan. However, Hartigan refuses to give in to Nancy as he saw her as a daughter figure, and that he is old enough to be her grandfather. Soon after, the yellow man was able to kidnap the two and he reveals who he really is, Roark Junior. He drugs Nancy and tries to hang Hartigan. Roark then calls a couple of his cronies to come and clean up the mess while he took Nancy back to the Roark farm. At the farm, he begins to torture Nancy with a whip, trying to get her to scream. However, Nancy was strong enough to keep from screaming, angering the yellow bastard even more. Hartigan would eventually catch up to them and kills Roark with his bare hands, even castrating him for a second time, in order to save Nancy. Hartigan took Nancy back to the car and tells her to take the car and go home. They kiss, wordlessly confessing their love for one another as soulmates. Hartigan tells her that he is going to call in some friends to put Roark behind bars. As Nancy drives away, Hartigan shoots himself in the head in order to keep Nancy safe.
The movie adaption of Sin City was released in 2005 directed by Robert Rodriguez and Frank Miller. Nancy Callahan was portrayed by Jessica Alba. The Sin City movie was a perfect adaption to the comic as it stayed very true to it.