Petty was born October 20, 1950, in Gainesville, Florida, the first of two sons of Kitty (nee Avery), a local tax office worker, and Earl Petty, who worked in a grocery store. He had a brother, Bruce, who was seven years younger. His interest in rock and roll music began at age ten when he met Elvis Presley. In the summer of 1961, his uncle was working on the set of Presley's film Follow That Dream, in nearby Ocala, and invited Petty to watch the shoot.

Petty's first appearance in film took place in 1978, when he had a cameo in FM. He later had a small part in 1987's Made in Heaven and appeared in several episodes of It's Garry Shandling's Show between 1987 and 1990, playing himself as one of Garry Shandling's neighbors. Petty was also featured in Shandling's other show, The Larry Sanders Show, as one of the Story within a story final guests. In the episode, Petty gets bumped from the show and nearly comes to blows with Greg Kinnear.  Petty appeared in the 1997 film The Postman, directed by and starring Kevin Costner, as the Bridge City Mayor (from the dialogue it is implied that he is playing a future history version of himself). In 2002, he appeared on The Simpsons in the episode "How I Spent My Strummer Vacation", along with Mick Jagger, Keith Richards, Lenny Kravitz, Elvis Costello, and Brian Setzer. In it, Petty spoofed himself as a tutor to Homer Simpson on the art of lyric writing, composing a brief song about a drunk girl driving down the road while concerned with the state of public schools. Later in the episode, he loses a toe during a riot.  Petty had a recurring role as the voice of Elroy "Lucky" Kleinschmidt in the animated comedy series King of the Hill from 2004 to 2009. In 2010, Petty made a five-second cameo appearance with comedian Andy Samberg in a musical video titled "Great Day" featured on the bonus DVD as part of The Lonely Island's new album Turtleneck & Chain.

What did he do after 2009
In 2010, Petty made a five-second cameo appearance with comedian Andy Samberg in a musical video titled "Great Day" featured