At the age of 32, Medearis was commissioned as a Second Lieutenant in the North Carolina Continental Line.
He was promoted to Captain on December 23, 1777. In 1783 he was advanced to the rank of Major. George Washington’s general orders of May 29, 1778, at Valley Forge mention Captain Medearis of the North Carolina Brigade. Medearis served as Assistant Deputy Quartermaster General to Colonel Nicholas Long. His pension file (S-2823) indicates that he was at Halifax, North Carolina, on November 3, 1778, as requested by Colonel Nicholas Long and Colonel Jethro Sumner, and assigned to the Quartermaster Department.
Medearis was given land grants in Bedford, Davidson and Hamilton Counties in Tennessee. In 1809, he moved his family to his land grant in Bedford County, now Marshall County, Tennessee. He named his new home “Liberty Valley,” the name it still bears today. Tennessee Historical Marker 3G12 stands near the location to commemorate his Revolutionary War Service.