An immigrant from St. Croix at the age of 17, Harrison played significant roles in the largest radical class and race movements in the United States. In 1912–14, he was the leading Black organizer in the Socialist Party of America. In 1917 he founded the Liberty League and "The Voice", the first organization and the first newspaper of the race-conscious "New Negro" movement. From his Liberty League and "Voice" came the core leadership of individuals and race-conscious program of the Garvey movement.