The Harlem Renaissance started in the late 1910s and went through the 1930s. Its causes are all localized in the many transformations America was going through the 1920s.
The age of anxiety was characterized by growing fundamentalism, blatant racism with the rebirth of the Ku Klux Klan and the mob attacks on black veterans of World War I known as the Red Summer, nativism, hatred of immigrants, hatred of non-Catholics, anti-communism that is known as the First Red Scare caused by the October Revolution (1917) in Russia, hatred for anything that looked like leftism and defense of worker's rights.
Many of these things were caused by and/or impacted by growing industrialization, consumer culture, government's encouragement of business. It was during this time that the Great Migration started: the event when millions of African Americans migrated towards the North to cities like New York, Detroit, Chicago, and Philadelphia.
All this together created a scenario of growing mass culture that generated more space, opportunities, and the need for black people to finally express themselves in art. It was in the works of the Harlem Renaissance that black authors defied racism and the lynchings they were suffering in the sphere of popular culture.
