From an early age, DJ, whose full name is Devon Montegomery Johnston the Third, was interested in all kinds of music. He had a voracious appetite for collecting records and was a gifted student at the nationally renowned East Coast Music Conservatory. One evening at a friend's party, Devon met a gentleman by the name of Wingo. An expert in paint and body modification, Wingo designed a custom paint job for Devon and a wicked sound system to match.
DJ is a member of the Tuner Cars. He has a built in sound system. He and the other tuners were driving along the Interstate when they noticed a sleepy Mack. They decide to have fun with him, with DJ playing Kenny G's Songbird to cause Mack to sleep, until Snot Rod's loud sneezing causes them to flee the scene. DJ later appears in the epilogue when he and the other tuners were caught by Sheriff and were impounded. They were later sent to pull Bessie, in which some hot tar splashed on them.
- DJ is a Scion XB, with modified spoilers and air dams.
- DJ is voiced by E.J. Holowicki, who is movie sound engineer and sound effects editor.