Joined the Mothers Of Invention in early 1967 and recorded and toured with Frank Zappa and the Mothers until late 1969. He was also a member of the Abnuceals Emuukha Electric Symphony Orchestra around 1967 when Zappa recorded the orchestral parts for Lumpy Gravy, playing flute, piccolo, clarinet, bassoon, bass, soprano and tenor saxes.

Shortly after leaving the Mothers, Gardner performed with Menage A Trois, with his brother Buzz and John Balkin. He also toured and recorded with Geronimo Black and with The Grandmothers. In 2003, he took part in a concert (and recording) of The Grande Mothers Re:Invented. Besides Gardner, the Grande Mothers Re:Invented also featured Don Preston, Napoleon Murphy Brock and Roy Estrada.