Son of 1940s and 1950s band leader Frankie Kaye and former nationally known radio personality during the 1960s during Top-40 radio era under the names "Lee Vaunce" at KGFJ in Los Angeles and "Mike Sheppard" at both San Francisco's KDIA and New York's WWRL. While a DJ at KPOI in Honolulu, Gwynne broke the Guinness Book of Records for nonstop drumming (92 hours) at the 1965 "Drum-A-Thon". He went on to sit in at the drums with many R&B bands of that era.

Arriving in Hollywood in 1969 to visit a friend, he met a man at a party who said he was the Universal Studios producer Jerrold Freedman. They hit it off over jazz music and radio, Gwynne even expressing an interest in acting and Freedman saying they would work together. Realizing he was at a "Hollywood" party, Gwynne did not believe the man was really a producer and dismissed the whole thing.

Three weeks later, Gwynne received a telegram instructing him to be at Freedman's office at Universal. Seems he really was a producer and when Gwynne arrived at the appointed hour, he was introduced to a man name Bob Edmiston who silently shook his hand then left the room. Gwynne gradually realized he was being offered a part on a show called The Bold Ones: The Senator (1970) directed by Daryl Duke, with whom he was to work in several other movies including Payday (1973) with Rip Torn, his first big break into features in 1971.

Soon after that first meeting, he met an excitable young man through an ex-girlfriend. He was looking for a break as a director. Freedman was again involved and the new director, Steven Spielberg was offered a TV show called "Par for the Course" and Gwynne was delighted to work with him playing a psychiatrist with Roy Thinnes and Clu Gulager. The beginning of a lifelong career in acting for radio, TV and the big screen had begun.

Gwynne is (2016) currently writing scripts and living happily in the woody Westchester region of New York, just above Manhattan where he still plays the drums from time to time sitting in at Showman's Club in Harlem.