Gales was born in Memphis, Tennessee. At the age of six, and along with his twin brother Daniel, Jimmy received an acoustic guitar. Naturally left-handed, he learned to play with the guitar upside down, and in his early teens graduated to an electric model. He started his musical career playing rock and roll, but in the 1980s he switched to playing the blues. Nevertheless, as was later noted, King often merged both genres in his playing. He joined Albert King's backing band in 1988, and the twosome formed such a friendship that Albert referred to Little Jimmy as his "adopted" grandson. At the end of this period, the latter formally changed his name to King. After leaving Albert King's band, Little Jimmy King formed his own ensemble, called Little Jimmy King & the Memphis Soul Survivors, and released his debut album in 1991 on the Bullseye Blueslabel. The Allmusic journalist Thom Owens described the disc as "an exciting, promising debut". In 1993, King had a small cameo role in the filmThe Firm, playing a street musician on Beale Street, in Memphis. King's next album was Something Inside of Me. It was produced by Ron Levy. On the recording King used various musicians, billed as the King James Version Band, and also utilised Tommy Shannon and Chris Layton, who were formerly part of Stevie Ray Vaughan's backing ensemble, Double Trouble. One music journalist noted that the album was "caught between traditional blues and its rock equivalent" and that King was an "uneasy amalgam of both disparate elements, which he struggled to mould into a recognizably individual sound". In 1995, King recorded with his brothers, Eric and Eugene Gales. The resultant album, Left Hand Brand, released on the House of Blues label, was billed as by the Gales Brothers. In addition, King played guitar on Ann Peebles's 1992 album, Full Time Love. He also backed Otis Clay on his albums I'll Treat You Right and On My Way Home. In 1997, Willie Mitchell produced King's third Bullseye Blues release, Soldier for the Blues. Cub Koda noted that the collection had a "more pronounced soul blues feeling than his two previous efforts". In September 2000, at Bobby Bland's receiving of the Blues Ball Pyramid Award, King played at the benefit tribute event. King died on July 19, 2002, in Memphis, after suffering a heart attack.