He practiced law in Fairbury, Nebraska from 1939 to 1940 and then became a special agent for Federal Bureau of Investigation from 1940 to 1941, serving in Washington, D.C., and Chicago, Illinois.

He enlisted in the United States Marine Corps during World War II, in October 1942, with the First Armored Amphibian Battalion.

He remained active in United States Marine Corps Reserve until 1960 and retired with rank of lieutenant colonel.

He assumed senior status due to a certified disability on April 16, 1981, serving in that capacity until his death on June 26, 1981, in Omaha, Nebraska.

[citation needed] On December 23, 1981, the Robert V. Denney Federal Building and Courthouse in Lincoln, Nebraska was named by President Ronald Reagan.