Bennes Mardenn was personally trained by the Group Theatre: Stella Adler, Bobby Lewis, Harold Clurman, Lee Strasberg, and his mentor, Morris Carnovsky.

In New York, Mardenn taught at Carnegie Hall, the 92nd Street YMHA, Educational Alliance, and was the Speech and Drama Director at Henry Le Tang’s Dance School.

In Hollywood, Mardenn opened a studio called the Drama Lab where he trained Talia Shire, Herschel Bernardi, Sal Mineo, Gary Crosby, Charlie Brill, Mitzi McCall, Richard Hatch, Danny Michael Mann, James Earl Jones, Diana Sands, and Kim Darby.

In Israel, Mardenn held the position of Director of Dramatic Activities and Events for the American Cultural Center.

As an actor, he has performed with and/or been directed by Montgomery Clift, Morris Carnovsky, David Opatoshu, Bette Davis, Katharine Hepburn, Jason Robards, Colleen Dewhurst, Herschel Bernardi, Harold Gould, John Randolf, Milo O’Shea, Ruby Dee, Ozzie Davis, James Farentino, Canada Lee, Didi Pheiffer, J.D.