This is a commentary on the corporate takeover of radio stations. In the late '90s, stations began computerizing their playlists and having DJs record their shows ahead of time, which saved money for the station owners. The practice of pre-recording a show is known as voice-tracking, and allows a DJ to tape a show from another location whenever he wants. Many station groups will have one DJ voice-track a bunch of shows on many different stations every day. Since the DJ is not local and is recording the show ahead of time, he cannot refer to timely events and must make an effort to connect with an audience he does not know.
Predictably, this song got very little airplay, which in a way proved Petty's point, something he would point out when he performed the song live.
Petty told Mojo magazine January 2010 that this song is often misunderstood. He explained: "Radio was just a metaphor. 'The Last DJ' was really about losing our moral compass, our moral center. We don't care who gets hurt any more in the quest for the dollar. That was what I was trying to say. My mistake was hanging so much of it on the music business; where had I been, under a rock?"
The influential KLOS disc jockey Jim Ladd is often cited as the inspiration for this song, and Petty wrote in the album liner notes, "Thanks to Jim Ladd for his inspiration and courage."
A California songwriter named Jim Wagner sued both Petty and Ladd over this song, claiming it was based on a song he wrote in 2000 called "The Last Great Radio DJ." According to the $4.5 million suit, Wagner claims he sent a demo of the song to Ladd, who then gave it Petty. Petty responded to the lawsuit, stating, "My song, 'The Last DJ,' was written completely without any outside influence. It is a wholly original composition. Claiming that Jim Ladd ever gave me another piece of music or discussed the plaintiff or his song with me in any way whatsoever is a total falsehood."
While Ladd is often referred to as "The Last DJ" from this song, he and Petty downplay his influence on the song. When Ladd was laid off from KLOS in 2011 as part of an industrywide purge of local disc jockeys, Rolling Stone referred to him as the inspiration behind the song.