[4] Returning from compulsory military service in 1932, his violin studies were put on hold because his father's cancer required Ronis to take over the family portrait business.

The work of the photographers Alfred Stieglitz and Ansel Adams inspired Ronis to begin exploring artistic photography.

[7] In 1937 he met David Seymour and Robert Capa, and did his first work for Plaisir de France; in 1938–39 he reported on a strike at Citroën and traveled in the Balkans.

[7] With Henri Cartier-Bresson, Ronis belonged to Association des Écrivains et Artistes Révolutionnaires, and remained a political leftist.

In 1953, Edward Steichen included Ronis, Cartier-Bresson, Robert Doisneau, Izis, and Brassaï in an exhibition at the Museum of Modern Art titled Five French Photographers.

[7] Ronis began teaching in the 1950s, and taught at the School of Fine Arts in Avignon, Aix-en-Provence where he met Pierre-Jean Amar and Saint Charles, Marseilles.

[7] Ronis continued to live and work in Paris, although he stopped photography in 2001, since he required a cane to walk and could not move around with his camera.

[4] Late in her life, Ronis photographed Marie-Anne suffering from Alzheimer's disease, sitting alone in a park surrounded by autumn trees.