On Oct. 2, the world will mark the 150th anniversary of the birth of Mohandas Karamchand “Mahatma” Gandhi. Gandhi never visited the U.S., but few non-Americans have had such a great impact on American life. His work as a freedom fighter and social reformer in India was closely followed in the U.S.

In the 1920s, when Gandhi launched a nonviolent mass movement against British colonial rule in India, his struggle was widely reported in the African-American press. Thinkers such as W.E.B. Du Bois and E. Franklin Frazier wrote...