Born in Boussy-Saint-Antoine, near Paris, in 1884, Dunoyer de Segonzac began painting in 1903, studying in Paris and frequenting the Académie de la Palette and the studios of Luc Oliver Merson and Jean-Paul Laurens. After military service he shared a studio with Jean-Louis Boussingault in 1907 and befriended Luc-Albert Moreau and Lucien Mainssieux. In 1908 he stayed for the first time in St Tropez, which became the setting for much of his work.
From 1909 Dunoyer de Segonzac exhibited regularly at the Salon des Indépendants, and he also took part in the Salon de la Section d'Or in October 1912 and in the Armory Show in New York in 1913. His paintings of this period reveal the influence of Cubism and occasionally that of Expressionism. On being conscripted in August 1914 he left St Tropez to join his army corps in Fontainebleau and during World War I he made a series of drawings in the trenches. After the War he was introduced by the French printmaker Jean Emile Laboureur to etching. This marked the beginning of his lifelong involvement with the medium: he produced more than 1600 prints.
In 1925, with Moreau and André Villeboeuf, Dunoyer de Segonzac purchased Charles Camoin's villa in St Tropez and rechristened it Le Maquis. Henceforth he stayed regularly, often meeting the writer Colette there and taking inspiration from the town and its environs. Undistracted by the dazzling light of the Mediterranean he devoted himself to transcribing the rare moments of dull grey light or cloudy skies, achieving a sense of timelessness and a melancholy mood. Influenced by Cézanne, he increasingly turned to watercolour at the end of his life. These ensured his commercial success and earned him official recognition, and he was made the curator of the Musée de l'Annonciade in St Tropez on its creation in 1955. He died in Paris in 1974.