From 1952 to 1955, Carmouche was a magistrate judge for the United States District Court for the Western District of Louisiana. He was from 1955 to 1984 an assistant state attorney general under Fred S. LeBlanc, Jack P. F. Gremillion, and William J. Guste. Carmouche was a delegate to both the 1956 and 1960 Democratic national conventions. In 1960, Carmouche served on the party platform committee and was a successful elector candidate for the Kennedy-Johnson ticket, which easily won the ten electoral votes in Louisiana.