Woodson became affiliated with the Washington, D.C. branch of the NAACP, and its chairman Archibald Grimké. On January 28, 1915, Woodson wrote a letter to Grimké expressing his dissatisfaction with activities and making two proposals: -That the branch secure an office for a center to which persons may report whatever concerns the black race may have, and from which the Association may extend its operations into every part of the city; and -That a canvasser be appointed to enlist members and obtain subscriptions for The Crisis, the NAACP magazine edited by W. E. B. Du Bois. Du Bois added the proposal to divert "patronage from business establishments which do not treat races alike," that is, boycott businesses. Woodson wrote that he would cooperate as one of the twenty-five effective canvassers, adding that he would pay the office rent for one month. Grimké did not welcome Woodson's ideas.
Du Bois used his influential role in the NAACP to oppose a variety of racist incidents. When the silent film The Birth of a Nation premiered in 1915, Du Bois and the NAACP led the fight to ban the movie, because of its racist portrayal of blacks as brutish and lustful.
Responding to Grimké's comments about his proposals, on March 18, 1915, Woodson wrote: I am not afraid of being sued by white businessmen. In fact, I should welcome such a law suit. It would do the cause much good. Let us banish fear. We have been in this mental state for three centuries. I am a radical. I am ready to act, if I can find brave men to help me. His difference of opinion with Grimké, who wanted a more conservative course, contributed to Woodson's ending his affiliation with the NAACP.
With the onset of World War I in late 1914, the Buffalo Forge Company, where Carrier had been employed for 12 years, decided to confine its activities entirely to manufacturing. The result was that seven young engineers pooled together their life savings of $32,600 to form the Carrier Engineering Corporation in New York on June 26, 1915.
As the orders for deportations and massacres were enacted, many consular officials reported what they were witnessing to Ambassador Henry Morgenthau, Sr., who described the massacres as a "campaign of race extermination" in a telegram sent to the United States Department of State on 16 July 1915. In memoirs that he completed during 1918.
Along with William D. Hartgrove, George Cleveland Hall, Alexander L. Jackson, and James E. Stamps, Woodson founded the Association for the Study of Negro Life and History on September 9, 1915, in Chicago.