Marie del Norte Theriot was born 14 October 1902 on Bayou du Large, Sunrise Plantation in Houma, Louisiana to parents Marie Daigle Theriot and Charles Otis Theriot. Her schooling included Lafayette Parish School, Southwestern Louisiana Industrial Institute (later University of Southwestern Louisiana; now University of Louisiana at Lafayette) where she received her Bachelor of Arts on 31 May 1921, and Columbia University in New York City where she received her Master of Arts on 28 October 1925. She married Jack G. Hains of Rayne, Louisiana; the couple had no children. Theriot died at the age of 84 on 25 September 1987 and is buried in Resthaven Garden of Memory in Baton Rouge, Louisiana.

Theriot taught French at Southeastern University in Hammond, and later joined the French department at University of Southwestern Louisiana where she taught for many years here. She was also a genealogist. Her interests included history, politics, and the history of Louisiana and Acadiana. In addition, Theriot produced a children's song and dance book entitled "Les Dances Rondes."