Jack Smith is a villain from the cartoon American Dad! He is the biological father of series protagonist Stan Smith, and first appears as the hidden main antagonist in the season 1 episode "Con-Heir". He also reappears in the season 4 episode "Jack's Back". He becomes an supporting character in the episode "Minstrel Krampus". His design and character are a parody of Marvel comic's Nick Fury and Escape from New York's Snake Plissken.
Before Minstrel Krampus, Jack's design is simply that of an older Stan. His character design is a parody of Nick Fury. He wears an eye patch where he keeps a herb drill.
As a father he never really cared about his family. He cared more about his riches and power instead. He would often steal things from family members and frame them for crimes that he committed. He also ignored Stan as a child in which, as a result Stan never learned how to do things like ride a bike. He lies to his relatives to just make himself sound like a better person. He however, does have a softer side as he seems to be concerned when Steve sees him as a better role model than Stan, and even feels that he could of been a better father to Stan as well.
Around the time of Stan and Francine's marriage he left Stan to go on a "mission". Stan decided to have someone pose as his father to trick his family for the next 20 years. However when the poser dies, Jack arrives at the funeral to reveal he was Stan's true father. He claims to be a member of an organization called the Scarlet Alliance, but is really a jewel thief that the police have been tracking down for years. At first the Smiths don't believe him, but when the police arrive at their house, and a mustache is found in his suitcase Francine grows suspicious. He eventually gets Stan to quit work at the CIA, and has him go on a mission with him to raid a museum, but the mission is really a robbery. During the robbery, Stan refuses to steal with him, and Jack decides to turn himself in. Later in the series Jack returns when Stan is upset that he never really had a father and Steve releases him from prison. At first he seems reformed, and is even willing to make up for lost times with Stan, and be a role model to Steve. But it turns out that Jack is due for a trial, and is using Steve for a character reference. Stan and Steve then run away but, Jack decides to go to trial anyway. Stan tries to help him at trial but, is too late and Jack is sent back to prison.
Later when Steve misbehaves in "Minstrel Krampus", his grandfather Jack tells the story of how, as a boy growing up in Lower Berchtesgaden in Southern Bavaria, he captured the legendary Krampus, Santa Claus' sidekick that punishes naughty children. Tired of Steve's brattiness, Stan allows the Krampus to go free but he kidnaps Steve and demands Jack be brought to him. But when Stan uses his CIA connections to free Jack, he instead flees, leaving Stan and Roger to try to make a deal with Santa who still bears a grudge after the events in "For Whom the Sleigh Bell Tolls" but is willing to go along in order to kill the Krampus.
Meanwhile, Steve discover that the Krampus only punishes children because he loves them and tries to set them straight and bonds with him, just as Stan and Santa arrive and Santa kills the Krampus before turning the gun on Stan. Jack, who has had a change of heart, takes the bullet meant for Stan. As Santa flees, Jack's and the Krampus' blood intermingle, transforming Jack into the new Krampus.