The series focuses on an eccentric motley crew that is the Smith family and their three housemates: Father, husband, and breadwinner Stan Smith; his better half housewife, Francine Smith; their college-aged daughter, Hayley Smith; and their high-school-aged son, Steve Smith. Outside of the Smith family, there are three additional main characters, including Hayley's boyfriend turned husband, Jeff Fischer; the family's man-in-a-goldfish-body pet, Klaus; and most notably the family's zany alien, Roger, who is "full of masquerades, brazenness, and shocking antics."
While running an errand in Little Columbia, Stan is confronted by his hidden past.
Hayley and Steve find themselves stranded in a suburban neighborhood.
Roger enlists Jeff as his protégé in order to open his dream strip club; Klaus moves into Steve’s room.
Roger tries to give Steve bubonic plague in order to qualify to Make-A-Wish to meet The Weeknd. Stan abducts The Weeknd to teach Roger a valuable lesson. Meanwhile, Hayley attempts to sleep with the celebrity singer.
Steve discovers his mom has never stopped giving him her breastmilk.
Stan and Steve enter an e-sports game tournament to save the world. The rest of the family get stuck in a banister.
When Stan sees a middle-school classmate, he feels compelled to right an old wrong; Roger feels a cold coming on.
Hayley tries to save Klaus from being deported
Jeff, Francine and Roger decide to team up and start their own bus tour business, with murderous results.
After Stan is injured, Francine nurses him back to health and he becomes dependent to her. The family discovers Tuttle is a Korean reality show star.
Stan drags the family to a labyrinth for family game night; Roger gets some geese.
Steve and the boys take part in a prison experiment to earn some cash. Meanwhile, Stan deals with the death of his CIA groundskeeper friend.
Steve's efforts to befriend a Swedish exchange student backfire in a big way; The family calls in an animal behaviorist to deal with Klaus.
Stan struggles to cope with the untimely death of his father. Meanwhile, a simple canoeing trip does catastrophic damage to Hayley and Jeff's relationship.
Klaus enlists Stan, Roger and Jeff to join him on a wild bachelor party weekend.
Concerned that Hayley is too soft-hearted, Stan attempts to make her "farm tough" by turning the house into an urban homestead.
When one of Roger's characters falls in love with Dick, it affects the whole family.
Steve wants to know about the Smith Family heritage, but Stan refuses to indulge him. Stan is obsessed with being American and tells Steve that being American is all that matters. Steve steals Stan's DNA for an at-home DNA test and discovers that they are Canadian. Steve rejoices in finally knowing his heritage, but the news devastates Stan.
Hayley takes off her headband and becomes a businesswoman; Stan plans a party.
Francine explores ASMR with Roger. Steve gets a a pole in his head and a secret admirer.
Stan goes to great lengths to find the "right" couple's activity for him and Francine; Hayley and Steve look into some mysterious markings they find on the door frame.
The Smiths take a trip on an old steam locomotive to visit Francine's aunt only to discover it's being hijacked.
American Dad becomes the 25th scripted primetime show in the History of Television to reach 300 episodes and Roger's past comes back to haunt him.