Barrett was born in
Lusk, Wyoming to
Frank A. Barrett and Alice Catherine Donoghue Barrett. He graduated from
Niobrara County High School in Lusk in 1940. As a teenager he wrote for the "Lusk Herald" and
The Denver Post. He served in the
United States Army during
World War II from 1942 to 1945, where he participated in the
Invasion of Normandy. He was assigned to the Headquarters Detachment of the 1st Army and 3rd Army and achieved the rank of corporal. After the war, he attended
Catholic University of America in Washington, DC for six months. He entered law school in the fall of 1946, he went to
University of Wyoming College of Law and received a
Bachelor of Laws in 1949. He was in private practice in Lusk from 1949 to 1967, serving as a prosecuting attorney in Lusk from 1951 to 1962, and as a town attorney from 1954 to 1956. He was secretary-treasurer of
Niobrara County Republican Central Committee from 1950 to 1966, and the attorney for the Niobrara Consolidated School District from 1952 to 1962. He became the
Wyoming Attorney General from 1967 to 1971. ==Federal judicial service==