The U.S. government did not allow African-Americans to join the U.S. Marine Corps until 1942.  The first black Marine was Howard P. Perry.

This photo, of Perry, is maintained at the U.S. National Archives.  Its description reads as follows:

Breaking a tradition of 167 years, the U.S. Marine Corps started enlisting Negroes on June 1, 1942.  The first class of 1,200 Negro volunteers began their training 3 months later as members of the 51st Composite Defense Battalion at Montford Point, a section of the 200-square-mile Marine Base, Camp Lejeune, at New River, NC.  The first Negro to enlist was Howard P. Perry shown here.

Bos, Carole “First African-American Marine – 1942” AwesomeStories.com.