Sid Grossman joined a camera club while in high school and began a career as a freelance photojournalist while attending City College. In 1936 he co-founded the Photo League with Sol Libsohn. In 1938-1939 he and Libsohn collaborated on a project documenting the changes taking place in Chelsea and in 1939 he worked on a series that documented street life in Harlem. In the summer of 1940 Grossman traveled through the dust bowl states and photographed union activities as well as rural life. During World War II Grossman's projects were focused on the war effort, and a War Production Group headed by Grossman in 1942-1943 photographed Red Cross activities, civilian defense, student volunteers doing farm work, and the care of young children. Grossman joined the army in 1943 and was stationed in Panama. During 1945 he photographed the Black Christ festival in Portobello, Panama, and traveled to Guatemala and the Galapagos Islands. Grossman enjoyed his most productive years as a photographer just after World War II. He photographed Coney Island in the summers of 1947 and 1948 and the San Gennaro festival on Mulberry Street in Manhattan's Little Italy in 1948. Grossman and the Photo League ran afoul of the FBI in 1949. He had been under surveillance since his trip to the Midwest in 1940, during which the FBI suspected him of associating with Communists. The FBI widened its investigation to include Grossman's associates at the Photo League and eventually concluded that the League was a Communist front organization and that some of its members belonged to the Communist Party. During a conspiracy trial an informant named Grossman as a Communist. Newspapers and magazines would no longer report on the League's activities. Membership declined, and the League was disbanded in 1951. Grossman spent the summers in Provincetown, Massachusetts after 1949, where he studied painting with Hans Hofmann and opened a school of photography. He also taught privately in New York during the winter months; among his students was Lisette Model, who enrolled with him in part as a gesture of support. His later work focused on the landscape and people of Cape Cod and was published posthumously in the 1959 book Journey to the Cape.