Greenbaum set out to write a religious rock song. He is Jewish, but instead of using a Jewish word for God, he used "Jesus" because he thought it would be more marketable. The single sold two million copies in 1969 and 1970 and reached number three in the U.S. Billboard chart, as well as number one on the UK, Australian and Canadian charts in 1970.
Greenbaum had previously been a member of psychedelic jug band Dr. West's Medicine Show and Junk Band. When they split up he won a solo contract with producer Erik Jacobsen, who had previously worked successfully with The Lovin' Spoonful. He was inspired to write the song after watching Porter Wagoner on TV singing a gospel song. Greenbaum was also influenced by Folk revival music and traditional Southern Blues.