Trimble earned a bachelor's degree in music from Southern Methodist University where he was a pupil of Mack Harrell.
In 1962 he made his professional debut at the Dallas Opera as Roderigo in Otello with Mario Del Monaco in the title role.
[5] In the 1960s and early 1970s Trimble was highly active singing leading roles with several German, Austrian, and Swiss opera houses, including the Badisches Staatstheater Karlsruhe, the Bern Theatre, the Deutsche Oper Berlin, the Hessisches Staatstheater Wiesbaden, the Opern- und Schauspielhaus Frankfurt, and the Vienna Volksoper among others.
[6] He made his debut with the Canadian Opera Company in 1971 as Pinkerton to Maria Pellegrini's Cio-Cio-San under conductor Alfred Strombergs.
[7] In 1974 he made his debut at the Opera Company of Boston as Toby Higgins in Rise and Fall of the City of Mahagonny under conductor Sarah Caldwell.