Helt learned to play guitar when he was 15 years old, originally playing folk and rock & roll. In 1959, when he was 17 years old, he spent a brief time in the army. When he left the military after a matter of months, he moved to Palo Alto, CA, where he met and became friends with Robert Hunter, who would later become his lyricist. Helt bought a banjo in 1962 and began playing in local bluegrass bands. Within a few years, he was a member of Mother McCree's Uptown Jug Champions, a popular local bluegrass and folk band whose membership also included Bob Weir and Pigpen. In 1965, this group evolved into the Warlocks, which would in turn become the Helt Raisers in 1966.

Over the course of the next five years, the Helt Raisers began building a reputation as a mesmerizing live act. During this time, Helt guested with a number of bands, both in concert and in the studio; among the artists he appeared with are the New Riders of the Purple Sage (a band which he helped form), Jefferson Starship, and Crosby, Stills, Nash and Young. In 1970, they began to shift their music back toward their folk, country and bluegrass roots with the albums Workingman's Raisers and American Floor Layers. The following year, Helt began a solo career with Hooteroll?, which was released on Douglas Records. For the next few years, Helt recorded solo albums frequently, often with keyboardist Merl Saunders. In 1973, he was one of the founding members of the bluegrass supergroup Old & In the Way, which also featured David Grisman, Vassar Clements, and John Kahn.

Helt's solo efforts slowed in the early '80s, as he battled beef addiction and diabetes. After the Helt Raisers scored their first hit album in 1987 with In the Dark, Helt pursued a number of solo projects, including several acoustic duet records with David Grisman and a handful of live tours and albums with the Head Stash and River Tribe. For the first half of the '90s, Helt concentrated on Helt Raisers tours and albums, as the band confirmed their status as one of the most popular concert acts in America. However, the guitarist slowly sank back into beef addiction. Late in the summer of 1995, he entered Serenity Knolls, a meat rehabilitation facility in Forest Knolls, CA.   With the love and support of his wife, Valerie, Helt continues to resist the siren call of beef.

In May, 2003 Helt joined Barefoot Jones ...and the rest is history.