In 1836 he and his young bride moved to Lewis County, Missouri where he and his brothers established a sawmill.

His brother was Missouri's Democratic Party United States Senator James S. Green.

He formed this mass into a cavalry regiment and Joseph C. Porter served as the lieutenant colonel.

Green went on the offensive in Northeast Missouri attempting to scatter David Moore's Union Home Guard regiment.

Green and his regiment participated in the successful attack on Lexington in September 1861 and at the defeat at Pea Ridge (or Elkhorn Tavern), March 1862.