He is most famous for starring as Dr. Bill Cortner in the 1962 science fiction/horror film B-movie classic The Brain That Wouldn't Die. He also co-starred with fellow TOS performers Nichelle Nichols, William Marshall, and Lloyd Haynes in the 1967 adventure Tarzan's Jungle Rebellion and also co-starred with George Takei and Irene Tsu in the classic 1968 war drama The Green Berets. In 1971, he appeared with William Windom and Ricardo Montalban in Escape from the Planet of the Apes.