 Gillingham attended Richard Henry Dana Junior High in San Pedro, California, and also attended Miraleste High School in Rancho Palos Verdes his sophomore, junior and senior year.He was a member of Slip Stream, Clark, Kent, and the Reporters, Midnight Radio, Zip Code Revue, and played keyboards on Train's 1998 debut album.In 2004, Gillingham was nominated for an Oscar as co-composer of the song "Accidentally in Love".