A native of Coshocton County, William Green followed in his father's footsteps and began his working life as a coal miner at age 16. Six years later, Green married Jennie Mobley, a Coshocton native in 1892, and they had six children. He rose rapidly in the leadership of the United Mine Workers of America, and he is best known for his work in trade unions.

Twice elected to the Ohio Senate, Green served in such leadership positions as president pro tempore and democratic floor leader.

During his time in the Ohio Senate, Green wrote and won passage of Ohio's first worker's compensation act in 1911. This act came at a time when progressive-era ideals conflicted with an impersonal industrial system where workers enjoyed few rights and little security.

Green, one of the outstanding American trade union leaders of the twentieth century, was known as a mild mannered leader. As president of the American Federation of Labor, Green was instrumental in shifting the labor union's strategy from confrontation to cooperation.

Although Green was an influential member of many national boards, councils, and commissions, he most notably served President Franklin D. Roosevelt on the Labor Advisory Council of the National Recovery Administration, and President Harry Truman appointed Green to the National Advisory Committee on Mobilization during the Korean War. Green passed away following a long illness in 1952.