He began his career playing with Ted Fio Rito from 1943-1945, and followed this with a slot in Buddy Morrow"s orchestra in 1947. He worked with Charlie Barnet in 1951 and following this with Jerry Gray, Charlie Parker, Stan Getz, Georgie Auld, Jerry Fielding, Skinnay Ennis, Les Brown, Dick Haymes, Jack Jones, Lena Horne, Ann-Margret, and Nancy Wilson. In 1957 he played with Oscar Pettiford and toured Europe in 1958 with Anita O"Day.
Additionally, he recorded with Tommy Dorsey, Vic Schoen, Howard McGhee, Francis Faye, Betty Roche, Nelson Riddle, Paul Broadnax, Charles Mingus, and Ben Webster.
In the 1960s, Trenner worked as a studio musician, and led The Steve Allen Show house band. He also did work with Bob Hope.