Onslow Stevens: Onslow Stevens. Actor: Them!. Son of character actor Houseley Stevenson, brother of actor Houseley Stevenson Jr., Onslow Stevens was highly active from mid-1920s at the Pasadena Community Playhouse, where his entire family worked frequently as performers, directors and teachers. he scored a major success on Broadway in "Stage Door" in 1936. He played many leading roles and even more character parts over the years. Although at first a stalwart and...