He became interested in politics and soon got involved in projects aimed at helping those on the bottom of society. Unsatisfied with his work, he traveled to London in 1912 and stayed in England for two years. During this time he paid close attention to the controversy between Ireland and England concerning Ireland's independence.

He was also exposed to the ideas and writings of a group of black colonial writers that came together in London around the African Times and Orient Review. Nationalism in both Ireland and Africa along with ideas such as race conservation undoubtedly had an impact on Garvey.

However, he later remembered that the most influential experience of his stay in London was reading Booker T. Washington's autobiography Up From Slavery. Washington believed African Americans needed to improve themselves first, showing whites in America that they deserved equal rights.

Although politically involved behind the scenes, Washington repeatedly claimed that African Americans would not benefit from political activism and started an industrial training school in Alabama that embodied his own philosophy of self-help. Garvey embraced Washington's ideas and returned to Jamaica in 1914 to found the UNIA with the motto "One God! One Aim! One Destiny!"

Marcus Garvey and his organization, the Universal Negro Improvement Association (UNIA), represent the largest mass movement in African-American history. Proclaiming a black nationalist "Back to Africa" message, Garvey and the UNIA established 700 branches in thirty-eight states by the early 1920s.

While chapters existed in the larger urban areas such as New York, Chicago, and Los Angeles, Garvey's message reached into small towns across the country as well. Later groups such as Father Divine's Universal Peace Mission Movement and the Nation of Islam drew members and philosophy from Garvey's organization, and the UNIA's appeal and influence were felt not only in America but in Canada, the Caribbean, and throughout Africa.