Simmons was born in Saint Paul, Minnesota, and his family later moved across the Mississippi River to Minneapolis.

There, he attended West Side High School and then the University of Minnesota, where he studied drama.

[2] While attending the university, Simmons competed in fencing and swimming, and also acted in a few theater productions.

Simmons interrupted his film career to serve as a flight officer pilot [3] with the Air Transport Command in World War II.

[1] In the 1970s, when acting roles became scarce, Simmons managed a mobile home park in Carlsbad, near San Diego.