Green earned an LL.B from Cumberland School of Law in 1893, being called to the bar that same year. He operated a law practice in Nashville until 1910, when he was elected as an associate justice of the Tennessee Supreme Court. He was subsequently re-elected in 1918, 1926, 1934, and 1942. Green became the chief justice of Tennessee in 1923, serving until his death. As of 2011, he holds the record as the person who served the longest on Tennessee's highest court.Jack W. Robinson, Sr., Tennessee Supreme Court Building: Stately Hall of Justice , The Chronicle: The Newsletter of the Tennessee Supreme Court Historical Society, Fall 2010. Page 12.
