Medley was born on September 19, 1940 in Santa Ana, California, to Arnol and Irma Medley. He attended Santa Ana High School and graduated in 1958. Medley was raised as a Presbyterian and started singing in a church choir. His parents had a swing band. He became interested in R&B music listening to black music radio stations.[4] An early influence he cited is Little Richard who he first heard when he was fifteen or sixteen years old, and later Ray Charles, Bobby Bland, and B.B. King.
Medley first formed a singing duo called The Romancers with his friend Don Fiduccia, who also played the guitar. He began to write songs and record multi-track recordings in his living room. At 19, he had two songs, "Womaling" and "Chimes of My Heart", recorded by vocal group The Diamonds. Medley and Fiduccia then formed a group called The Paramours in 1960 with Sal Fasulo and Nick Tuturro, later joined by Mike Rider and Barry Rillera. The band had their first paying gig at Little Italy restaurant in Anaheim. The Paramours were signed to Mercury Records' subsidiary label Smash Records, and released songs such as "That's The Way We Love" and "Miss Social Climber" in 1961.