Jeff Fischer is Hayley's husband, however prior to their elopement they had been a frequently on again off again couple. In "Haylias", Hayley was looking to leave the country, but is brainwashed by Stan Smith to stay and marry a Senator's son who turns out to be gay. In "100 A.D.", Jeff decides to elope with Hayley, which the whole family is against.
Jeff was brutally beaten by Stan's boss, Avery Bullock in "Bullocks To Stan". He was left bleeding and twitching on the floor of a diner after being thrown head-first into a wall, but seems to have made a full recovery. He has also recovered from being crushed under a heavy object in "Phantom of the Telethon" and having all his skin peeled from his body by Roger in "Love, American Dad Style".
Until "Joint Custody", Jeff had not spoken to his father for years and "his mother ran away before he was born". In that episode, he went to his father Henry Fischer's farm in Raleigh, North Carolina, when trying to escape from Stan and Roger. Jeff is wanted in Florida for possession of marijuana as he had skipped bail.
In "Naked to the Limit, One More Time", Jeff discovers about Roger being an alien and Stan has to kill one of them so the CIA wouldn't find out and risk his family. When Roger asks Jeff for a hug before he leaves, Roger tosses him into a tractor beam from a ship sent to pick him up from his home planet which takes Jeff away, leaving a stunned Hayley behind.
In "Lost in Space", he is forced to reveal the trickery of Emperor Zing in hiding true love from his people, setting off a revolution and escapes in a spacecraft, looking for a way to get back to Earth and to Hayley.
In "The Longest Distance Relationship", Jeff is able to communicate with Hayley though a CB radio and discovers a way to return to earth through a wormhole, but arrives 60 years in the future and learns that he cost her a chance to have a great life with Millionaire Matt Davis. Unhappy with having upset the family and giving the elderly Hayley a heart attack, he returns through the wormhole and tells the again-young Hayley to move on with her life as he sadly gives up on her, unaware that Matt is killed by Roger very shortly after.
- A Flute that summons a Leprechaun.You can only use it three times, so choose wisely.
- Two ponchos
- Jeff is based on Seth MacFarlane's friend, also named Jeff Fischer, who voices the character.
- Jeff tells Hayley that he was born in the front seat of his van where she is sitting in "Stan Knows Best"
- In "The People vs. Martin Sugar", it is revealed that if he does not smoke weed, Jeff masturbates constantly.
- In "100 A.D.", it is hinted that Jeff smells like cheap weed and applesauce. Also in the same episode, his van has the ability to shed its cover and turn into a version of Chitty Chitty Bang Bang, which he shows to Hayley after they get married. Also, according to Jeff, he has a small penis.
- In "The Unbrave One" it is revealed that Jeff has a younger brother that their dad likes better.
- Although he is married to Hayley, he remains unaware of Roger being an alien in "Stan's Best Friend". Previously in "Dr. Klaustus", he believes that Roger is attracted to him.
- Also in "Stan's Best Friend", it's revealed that he is allergic to penicillin and that Jeff was a multimillionaire widower with a step-daughter named Patricia and a former cook for the band Blues Traveler and owned the rights to their first album. However, he gave the rights to his step-daughter as a fiftieth birthday present.