Danny DeVito first appeared on The Simpsons in season 2 of the series, in the episode “Oh Brother, Where Art Thou?”. He played Herbert Powell (according to The Simpsons Wiki), Homer Simpson’s (Dan Castellaneta) long-lost half-brother and a hugely successful Detroit auto designer—at least until Homer comes along and ruins his life. The character then appears again in the Season 3 episode “Brother, Can You Spare Two Dimes?” where he forgives Homer for the events in the previous episode and gets his fortune back.
DeVito’s Herbert was mentioned a few times throughout the show, and he had an additional voice-only cameo for the season 24 episode “Changing of the Guardian.” Considering that he first appeared in Season 2, DeVito was one of the first major celebrities to lend his voice to The Simpsons and likely helped open the door for more A-listers. It was an interesting decision to have him play the main character’s half-brother, but it’s obviously a decision that paid off, as the character was memorable throughout the show.