Marie-Lucie Nessi-Valtat was born in Paris, and upon completion of high school at the age of sixteen, convinced her parents to let her attend drawing school. After two years of study, Nessi-Valtat attended workshops at Billoul et d’André L’hôtel, l’Académie de la Grande Chamière, and l’École des Beaux-Arts.
She made friends with other artists in the cafés of Montparnasse and married in 1932. Until WWII, Nessi-Valtat and her husband traveled throughout Europe, which broadened and inspired her use of color. In 1949, they were divorced and Nessi-Valtat was left alone with her three children. In order to provide for her family, she began a small ceramics factory until she received help from her mother-in-law, and was able to devote all of her time to painting.
In 1972 she signed an exclusive contract with Wally Findlay Galleries, which afforded her a more international audience and financial security until the end of her life.