Following high school, Patrick attended Loyola Marymount University, where he was a member of Alpha Delta Gamma fraternity; he graduated in 1961. During this time, he struck out on his own to star in his own film The Young Land (1959). Patrick enlisted in the United States Coast Guard in 1961. He supported his father in The Alamo, Donovan's Reef, McLintock! and The Green Berets. He also appeared in Ford's sprawling epic Cheyenne Autumn (1964), as James Stewart's son in Shenandoah (1965), in An Eye for an Eye (1966), The Deserter (1971), and in a lead role in The Bears and I for Walt Disney (1974). Patrick also served a tour of duty with the United States Coast Guard from 1961 to 1965.