Volz showed great skills in singing from a very early age. Being a self-taught musician, when he was 13 years old, he started his own band called The Wombats. As he grew up, he went on to share the stage with the likes of Janis Joplin, Chicago and others. In 1970 he became a born-again Christian and started performing with several Christian bands. He formed a band called Gideon's Bible, and later toured with a group known simply as E Band, which was a part of the Jesus Movement. E's only studio recordings can be found on the rock musical 2LP-album Because I Am released in 1973. After e broke up in 1975 Volz moved to Springfield, Missouri, where he worked with legendary guitarist Phil Keaggy. He also performed the lead role in a rock stage musical called Ezekiel.

In 1976, Volz received two of the most important calls of his life. First, he was offered the lead singer position of REO Speedwagon. Volz, being a recently converted Christian, declined. Six weeks later, he got the call to participate in Petra's second album, Come and Join Us. Although at that time he participated as a guest singer in just three songs, founder/guitarist Bob Hartman (who, at that time, was sharing the lead-singing duties with co-founder/guitarist Greg Hough) offered Volz the full-time position.

His first full-time album with the band, Washes Whiter Than, came in 1979. Never Say Die (1981), More Power to Ya (1982), and Not of this World (1983) followed. Petra then changed sound slightly with new keyboard player John Lawry on 1984's Beat the System and reached the pinnacle of the Volz era. They played 285 dates to 500,000 people overall on the subsequent tour and resulted in a live album, Captured in Time and Space. With Greg X. Volz as the front man, Petra  came one of the most prolific periods of the legendary band. Volz remained the lead singer until 1985 when he left to pursue a solo career. Volz released his first solo effort, titled The River is Rising in 1986 under Myrrh Records. He followed it with three other moderately successful albums. During this time, he also toured with Joe English in a band called Pieces of Eight. Volz' tours drew in the 1,000 to 1,500 range during this time - a very respectable number for a Contemporary Christian artist, but no where near the level he experienced at the end of his tenure with Petra.

In October 4, 2005 he re-joined Petra for the live recording of their last DVD, Petra Farewell. He joined the stage with current singer John Schlitt for a medley of ballads, and he followed it with a solo rendition of "Grave Robber", which was one of his hits with the band.

In 2010 he spear-headed the renewal of the classic members of Petra from the early 80's. Classic Petra was born. Greg X. Volz, John Lowry, Louie Weaver, Mark Kelly and Bob Hartman took the band on a 2 year world tour with new recordings of the classic songs. 

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In 2016 Greg, Louie and John agreed to record another album of classic Petra songs and recruit the talent of former Petra member, Ronny Cates, and former Pieces of Eight Member, Kirk Henderson. Greg Bailey, another former Petra member, was asked to play bass on the 2018-19 tour. This new project is called CPR.