Duval was born to Stanwood Duval (1868–1928), and the former Mamie Richardson. Claude Duval and his older brother, Stanwood Richardson Duval, Sr., attended the [[United States Marine Corps]] reserve officers training school in Quantico, [[Virginia]], where they were jointly commissioned on October 31, 1942, as second lieutenants. The brothers served during [[World War II]] with the First and Third battalions, 23rd Marine Regiment of the 4th Marine Division. They landed in the assault waves in the seizure and capture of the [[Pacific]] islands of [[Saipan]], Tinian, and [[Iwo Jima]]. Stanwood Duval wrote a memoir of his war experiences, which he dedicated to the 3,298 officers and enlisted men of the 4th Marine Division who lost their lives in the fighting.
After the war, Claude Duval resumed his Houma law practice, which became Duval, Funderburk, and Sundbery. Stanwood Duval established a successful [[insurance]] agency. Both were active in their community. In 1957, Claude Duval was named president of the Houma branch of Rotary International.<ref>Houma, LA, Rotary Club history:http://www.houmarotary.org/HoumaRotaryHistory.cfm</ref>
==Race for lieutenant governor==
In 1963, Duval ran for lieutenant governor on the intraparty "ticket" of former [[New Orleans]] Mayor (and also former Ambassador to the [[Organization of American States]]) deLesseps Story "Chep" Morrison, Sr. (1912-1964). He was the [[conservative]] balance to the more "moderate" Morrison. In his own race, Duval was pitted against Clarence C. "Taddy" Aycock (1915-1987) of neighboring St. Mary Parish, who agreed with Duval on many issues. Aycock was informally paired with [[John J. McKeithen]] in the Democratic runoff though he was actually an independent candidate who made no alliance with any gubernatorial candidate that year. Aycock had the advantage in experience and name recognition.