He graduated from USMA in 1949. In April 1950, he married Ann née Brown. As a lieutenant, Steffy served in the Korean War, where he suffered frostbite and was wounded in the foot by a grenade. Due to his injuries, he was evacuated from Hungnam to Japan, and later awarded the Bronze Star Medal.
After the war, Steffy served on the Army football staff as the freshman team coach. He later owned a car dealership in Newburgh, New York. With his wife, who died in 2004, he had one son. Steffy died of a heart ailment on May 22, 2011 in Newburgh, New York at age of 85.