He graduated from the United States Military Academy at West Point, New York, in 1948 with a Bachelor of Science degree and a commission as second lieutenant.

From October 1967 to November 1968, he flew more than 200 combat missions, including an air strike in the A-1 Skyraider for which he received his second Distinguished Flying Cross.

Under his direction the center established one of the best flight safety and test aircraft utilization rates in the Air Force Systems Command.

[2] Upon retirement, Mathis and his wife, Greta, founded Eagle Mount, a nonprofit organization for therapeutic recreation in Bozeman, Montana.

Eagle Mount provides recreational services for people of all ages with physical and developmental disabilities and summer camps for children with cancer.