He was born in Norman, Oklahoma and learned to play several instruments, including banjo and guitar before he started high school. After he graduated, he played in a number of bluegrass bands. He debuted on the national scene with the country rock band Pure Prairie League in 1979, appearing on that band's album Can't Hold Back.

Gill appeared on two subsequent albums along with his then current wife, Janice Gill before signing as a solo with RCA Records in 1983. He first charted while on that label. In 1989 he switched to MCA Records where he recorded his breakthrough hit "When I Call Your Name." His 1998 album The Key received great critical acclaim, and is considered by some to be among the best country music albums ever released. His other albums include Next Big Thing (2003) and Let's Make Sure We Kiss Goodbye (2000).

Gill hosted the CMA Awards every year from 1992 to 2003. In 2004 he received a Grammy Award for Best Male Country Vocal Performance. In 1997, he was inducted into the Western Performers Hall of Fame at the National Cowboy & Western Heritage Museum in Oklahoma City, Oklahoma.

Gill married pop singer Amy Grant in March 2000. He divorced country singer Janis Gill of Sweethearts of the Rodeo fame, in 1997.

Dire Straits leader Mark Knopfler was a fan of Gill's, and had asked Gill to join the band full time. Gill turned down the invitation but did sing backup on one song ("The Bug") from Dire Straits' album On Every Street.