Max and Walter Löwenherz fled Germany in the 1930s to join their brother Heinz in Amsterdam, where he had a photo agency. It is not known if Max and Walter already had a picture agency in Germany. Max and Walter then succeeded in emigrating to New York, while Heinz and his family were arrested when the Netherlands were invaded by German troops and died in a concentration camp. The name of the photo agency, “Three Lions”, is in honour of the three brothers and a reference to their surname Löwenherz, which means lionheart.

Among the émigré photojournalists represented by the agency were Kurt Severin (who made a portrait series of Stefan Zweig in New York and was also a freelancer with Black Star Agency), Stefan Lorant and Germain Kellerman.
Sensitive about their own Jewish backgrounds and experiences of anti-semitism, the agency's proprietors advised émigré photographers to Americanise their surnames. Among those who followed this advice was Jack Mendelsohn (1920-2001), born the son of Romanian emigrants on the Lower East Side, who changed his name to Jack Manning. Trained at the Photo League, Manning sold his work to the Black Star Agency as well as to Three Lions.
Photo credits to be found in several issues of Life magazine attest to the fact that Three Lions provided an international network to photographers from all over the world. Among these were German émigré Hugo Brehme in Mexico City (Life, 17 April, 1944) and Christian Straub in Vienna (Popular Photography, February 1981, p. 35). Under the slogan "Our cover pictures are known everywhere” (Art Direction, vol. 19, 1967, p. 117) the agency's pictures appeared in advertisements.
Located at 545 5th Avenue, the agency was close to Grand Central Station and to other photo agencies founded by German émigrés, such as Rapho Guillemette, PIX Inc., Camera Feature, Photo Representatives, Monkemayer, European Picture Service and photo labs (Leco Photo Service, Service Photo Suppliers, Modernage, Spiratone, Pavelle Laboratories) and the headquarters of several magazines (Life, Look, Popular Photography, Graphic House).