He served in the United States Naval Reserve during World War II, from 1942 to 1945, achieving the rank of Lieutenant.
[1] On July 18, 1955, Estes was nominated by President Dwight D. Eisenhower to a seat on the United States District Court for the Northern District of Texas vacated by Judge William H. Atwell.
Estes was confirmed by the United States Senate on July 28, 1955, and received his commission on August 1, 1955.
He served as Chief Judge from 1959 to 1972 and as a member of the Judicial Conference of the United States from 1969 to 1971.
He served as a Judge of the Temporary Emergency Court of Appeals from 1972 to 1987.