The band was formed in 1998 by Steve Gulley, Barry Abernathy, Adam Steffey, and Van Cleve. Johnny Dowdle was the original bass player. For a short period, Steffey left the band to play with The Isaacs, a bluegrass gospel group. During that period, Steffey was replaced by mandolinist Alan Perdue. After their debut album, Dowdle left the group, and was replaced by former James King bass player Jason Moore. After Steffey's return to the group, Mountain Heart added virtuoso guitarist Clay Jones to the lineup. In September of 2007, Jones was replaced by Grammy Award winning guitarist, Clay Hess. Hess has played with such musical talents as Ricky Skaggs and Kentucky Thunder, and the Mark Newton Band. Mountain Heart has been with the Skaggs Family Records label since 2002.

In December 2006, the band announced that Steve Gulley would be leaving the group to form a new band, called Grasstowne. On January 5, 2007, Josh Shilling debuted with the band at the Grand Ole Opry in Nashville, TN, and was announced as the group's new lead singer.

The group's instrumental and vocal prowess are widely acclaimed in bluegrass and other acoustic music circles. The band was awarded the IBMA Emerging Artist of the Year award in 1999. They have been nominated for several other IBMA awards, including "Instrumental Group of the Year for 2006. Adam Steffey has won four IBMA awards for "Mandolin Performer of the Year", and Jason Moore has been nominated for "Bass Performer of the Year" for 2006.