Born in Atkinson, Nebraska, Hendricks began playing the guitar and single-loop steel guitar at a young age and made public appearances while working as a teacher in Omaha, Nebraska in the early 1960s. Cass Elliot attended one of his shows, and he invited Hendricks to join her and Tim Rose in the New York folk group The Big 3. The group successfully performed The Bitter End, toured with comedian Bill Cosby and appeared on The Tonight Show.

Hendricks married Elliott in 1963, but the marriage was called off in 1968. In 1964, Elliot and Hendricks formed the civic group The Mugwumps, which included Denny Doherty, John Sebastian and Zal Yanovsky. The group lasted eight months before Sebastian and Yanovsky formed The Lovin’ Spoonful and Doherty, and Elliot became half of The Mamas & the Papas. Hendrix moved to Los Angeles and formed Childhood Lights, which released three unsuccessful singles on Dunhill Records in 1966-67. While in the band, he improved his songwriting, and after leaving, he wrote the hit “Summer Rain” for Johnny Rivers and “Long Lonesome Highway”, the theme song for the TV series Then Came Bronson.
In the 1970s, Hendricks moved to Nashville, Tennessee, and began touring and composing contemporary Christian music with his family. Hendricks played guitar, mandolin, dobro and automatic harp and recorded over 50 albums covering a variety of styles, mainly American, country and contemporary Christian, including several instrumental albums on Benson Records and later Maple Street Music, with Who has worked with him. Founded in 1996.