The Tanner family is an average American family. One day, they discover that they have a visitor. He's small, he's furry, he's arrogant, and he's an alien from the planet Melmac. Unsure what to do, they name him ALF: Alien Life Form. Alf soon decides that as much as he misses his home planet, there's a lot to be said for Earth: the Tanners are willing to concede anything as long as he doesn't announce his presence. Oh yeah, the the Tanners also have a cat, which looks rather tasty...
Gordon Shumway, last known survivor from the planet Melmac, crash-lands his spaceship into the Tanner family's suburban garage. Willie dubs him "ALF", short for Alien Life Form. After convincing a military officer that they are not harboring a space creature, the Tanners decide to take ALF in as a member of the family.
ALF decides to have some fun while a nervous Mrs. Ochmonek baby-sits Brian.
When Lucky the cat disappears, everyone pins the blame on ALF.
ALF calls the president to address his concerns about nuclear weapons.
ALF takes a job selling cosmetics over the phone.
ALF befriends a lonely blind girl.
Willie helps homesick ALF arrange a trip to Melmac.
ALF has a crush on Lynn, so he makes a music video to impress her.
On his 45th birthday, Willie feels unfulfilled, so ALF suggests he go skydiving.
ALF sells parts of his spaceship to buy Lynn a Ferrari.
Willie loses his temper with ALF during a family camping trip.
It's Christmas time. Unfortunately ALF chops the Christmas tree into firewood before anyone notices. The Tanners then have two tasks: to teach ALF all about Christmas and find a new Christmas tree.
ALF heads for the garage when Kate's mother pays a visit.
ALF submits scripts to his favorite soap opera.
ALF plays matchmaker for Kate's mother.
ALF hits his head and is convinced he is an insurance salesman. The Tanners try reviewing past events to try and jog his memory.
The Tanners continue to try and jog ALF's memory, and deal with the police at the same time.
ALF befriends a young Mexican immigrant.
ALF goes through a 24-hour period of bizarre behavior.
Willie and ALF both talk to a psychologist.
ALF thinks he witnessed a murder at a neighbor's house.
ALF comes to Brian's aid when the boy has to play an asparagus in the school play.
ALF develops a gambling habit and winds up in trouble with his bookie.
Brian causes trouble at school when he repeats some of ALF's intergalactic knowledge.
A cockroach from ALF's spaceship grows to gigantic proportions