Farley was born on February 15, 1964, in Madison, Wisconsin. His father, Thomas John Farley, Sr. (1936-1999), owned an oil company, and his mother, Mary Anne (nee Crosby), was a housewife. He had four siblings: Tom Jr., Kevin, John, and Barbara. His cousin, Jim, is the CEO and Chairman at Ford Motor Company Europe.

Farley was originally cast as the voice of the title character in the movie Shrek, recording 85% of the character's dialogue, but died just before recording was finished. A story reel featuring a sample of Farley's recorded dialogue was released officially in 2015. The original version of Shrek was more like Farley himself, according to his brother. Farley was slated for another voice role in Dinosaur as a young male brachiosaurus named Sorbus who, despite his gigantic nature, was frightened of heights. After his death, the character was rewritten as Baylene, an elderly female Brachiosaurus played by British actress Joan Plowright. At the time of his death, Farley had been in talks to costar with Vince Vaughn in The Gelfin, and to star in a biographical film about comedian Fatty Arbuckle. Jim Carrey's role in the 1996 film The Cable Guy was originally intended for Farley, but scheduling conflicts forced him to decline. Farley was slated to appear in a third Ghostbusters film, which was at the time intended to be about a new trio of Ghostbusters taking on overpopulation in Hell. Dav Pilkey, author of the children's book series Captain Underpants, had wanted Farley to play the title role in a potential television series based on the books, but discarded the idea after Farley's death. Farley had been in talks for the lead in an adaptation of the novel A Confederacy of Dunces. Farley even expressed interest in portraying Atuk in an adaptation of the novel The Incomparable Atuk. Both of these shelved projects, along with the Arbuckle biopic, have been alleged to be cursed as Farley, John Belushi, and John Candy were each attached to all three roles, and all three died before any of the films entered production.

What was another unfinished work?
Jim Carrey's role in the 1996 film The Cable Guy was originally intended for Farley, but scheduling conflicts forced him to decline.