Samuel Klausman Lawrence Parks was born in Olathe, Kansas, on December 13, 1914, of German and Irish descent. As a child growing up in Joliet, Illinois, he was plagued by a variety of illnesses, including rheumatic fever, but persevered with physical exercise and sheer strength of will. Majoring in science at the University of Illinois, his plans to become a doctor dissolved when, to the dismay of his parents, he found a passionate sideline in college dramatics. He began appearing in touring shows, then made the big move to New York, finding initial employment as an usher at Carnegie Hall and a tour guide at Radio City. Following a number of summer stock shows, he made an inauspicious 1937 Broadway debut with a minor role in the Group Theatre's presentation of "Golden Boy". Developing a close-knit relationship with the Group, he was just beginning to build up his resumé in such Broadway outings as "All the Living", "My Heart's in the Highlands" and "Pure in Heart" when he had to return to his Illinois home following the death of his father.