Little is know about Gerber before his creation of the Society for Human Rights. He was born Josef Heinrich Dittmar in a small town in Bavaria on June 29, 1892. He immigrated to the U.S. in 1913 and enlisted in the U.S. Army, but had to declare himself a conscientious objector when the U.S. declared war on Germany. He moved to Chicago and worked briefly for the Montgomery Ward Company, but reenlisted with the Army after the war and subsequently got assigned to Germany during the years leading up to the formation of the Society of Human Rights.
Gerber found inspiration in fighting for gay rights while assigned to Germany (1920-23). There, he witnessed the German movement for homosexual emancipation and, in fact, found freedom in Berlin living as a homosexual. That experience led him to see the political importance and social implications of declaring a homosexual identity rather than have defined merely by individual, physical acts.
When he returned to Chicago in 1924, he formed The Society for Human Rights, which many argue is the first organization to openly advocate for gay rights, operated from 1924 to 1925. The organization produced the first two known gay-rights publication known as Friendship and Freedom, financed almost entirely by Gerber and typed on Gerber's typewriter that, in 1925, was seized when the police raided Gerber's home and arrested he and his fellow members.
The charges were eventually dropped, but Gerber lost his job because newspaper accounts of the raid ostensibly outed him. The raid also put an end to the work done by The Society for Human Rights; no other LGBT documentation emerged in Chicago for another thirty years after the raid. After the raid, and similar to the thousands of other gay men at that time, Gerber consistently was the subject of arbitrary arrests and imprisonment. Despite those injustices, Gerber remained a gay-rights activist well into the 1960s.