He began playing the guitar at the age of seven, and when he was 15 he made his first public appearance as a singer and performer in the Knoxville variety show Jim Clayton Startime.

[2] After completing Oak Ridge High School in 1973 he hitchhiked to Nashville with hopes of starting a music career.

[2] As a songwriter, early successes includes David Allan Coe's 1981 hit "Tennessee Whiskey".

Dillon has written many singles for George Strait, including "Unwound", "Down and Out", "Marina del Rey", "The Chair", "Nobody in His Right Mind Would've Left Her", "It Ain't Cool to Be Crazy About You", "Ocean Front Property", "Famous Last Words of a Fool", "I've Come to Expect It from You", "If I Know Me", "Easy Come, Easy Go", "Lead On", "The Best Day", "She Let Herself Go", "Living for the Night", "Here for a Good Time", "Drinkin' Man", "I Believe" and "Every Little Honky Tonk Bar".

[9] Dillon has worked with a younger generation of country stars including Toby Keith and Kenny Chesney.