Unable to sufficiently provide for her children in North Carolina, Green's mother in 1857 decided to relocate to Cleveland, Ohio, which promised greater educational and economic opportunities.

In Cleveland, liberal white community leaders mostly of New England origin encouraged tolerance, racial fairness, and integration even during the antebellum times.

"[2]: 15  Cleveland at that time already had a small cadre of prominent black citizens, such as George Peake, land developer and inventor; Madison Tilly, an excavating contractor; Dr. Robert Boyd Leach, a physician; John Brown, the proprietor of the barber shop in one of Cleveland's finest hotels, the New England House; and Freeman H. Morris, an owner of tailoring establishment, among others.

[2]: 18 Green attended local grammar and high schools which were already integrated in Cleveland, making parallel efforts to help his struggling family by working odd jobs; he was an errand boy, and in 1862 became a hotel waiter.

He continued to study on his own, and in an unusual attempt to secure funds for his further education wrote and published at his own expense a thirty-eight page pamphlet, Miscellaneous Subjects by a Self-Educated Colored Youth (1866).

In the Fall of 1872, Green returned to Cleveland where he was elected as a Justice of the Peace for Cuyahoga County, Ohio by a majority of 3,000 votes; he served three terms deciding close to 12,000 cases.

He supported state funding for Wilberforce University, an institution affiliated with the African Methodist Episcopal Church, and helped to defeat attempts to allow local school districts to practice racial segregation.

His efforts were appreciated and in 1897 he was awarded with a newly created position of U.S. Postage Stamp Agent in Washington, D.C., with an annual salary of 2,500, serving in 1897–1905.

"[7] In 1897, in a notable case, Green defended in Charleston, West Virginia a black servant who acted in self-defense, but was charged with assault.

[2]: 118  After coming to Cleveland at the age of twelve, he used available educational opportunities as a social lift and later employed politics as a tool of upward mobility, eventually becoming a prominent figure in Ohio Republican Party.

[2]: 119  However, Green is criticized by historians for silence and inactivity during increasing racial oppression and disfranchisement of the African-Americans in the South at the turn of the century, despite having access to many prominent political and social leaders, such as Marcus Alonzo Hanna, William McKinley, and John D. Rockefeller, among others.