Like many of the Scotch-Irish who settled the Shendandoah Valley, Samuel promoted religion and education. He was a founder of Timber Ridge Presbyterian Church and was also a trustee of Liberty Hall Academy, the precursor to Washington and Lee University. Here, future surgeon Ephraim McDowell took some of his first lessons. Although Samuel vigorously supported education, he had no formal schooling. But, as one early Kentucky historian remarked, "The most valuable lessons taught him were those of self-reliance, love of liberty, and fear of God; that these were sown on good and fruitful soil, the record of his whole life attests."
Like many Rockbridge County settlers, McDowell also saw military service on the Virginia frontier. He was a captain in Lord Dunmore's campaign against the Shawnee Indians, where he participated in several fierce battles. In one fight, Kentucky historian Thomas M. Green noted, most of McDowell's fellow officers were either killed or wounded. Unscathed, Samuel took charge of the battered band of frontiersmen "and snatched victory from the jaws of disaster." McDowell also served with the Virginia militia in the French and Indian War.
Samuel also was active in politics and government. When Rockbridge County was formally established, he represented the fledgling county in the Virginia House of Burgesses. Later, when conflict with Great Britain loomed, he represented his county in several conventions that urged colonial independence. In March 1775, he attended a conference in Richmond, Va., and the next year went to Williamsburg to urge the Virginia colony to secede from Britain. Samuel was one of the first Shenandoah residents to call for Virginia's independence. In fact, historian Taylor Sanders wrote, "McDowell had erected the first Liberty Pole in the Valley." The call for liberty again led McDowell to war.
During the American Revolution, Samuel served as a colonel in the Virginia militia. He fought in Virginia and in North Carolina, where his men proved themselves against British regulars at Guilford Court House. This battle, however, proved to be a British victory, and several prominent Virginians were killed or captured. When the war ended and independence was secured, Samuel was awarded a Kentucky land grant for his service. Although he was an influential resident of Rockbridge County, new lands beckoned. In 1784, Samuel and his family moved to Mercer County, Kentucky.
His prominence in the bluegrass grew rapidly
Samuel's prominence in the bluegrass grew rapidly. Upon his arrival he became a surveyor for public lands in Fayette County, which then comprised one third of Kentucky.
In March 1783, Kentucky County of Virginia was made into one judicial district. This proved to be a watershed event for Samuel's political career. As Mercer County was growing rapidly, Harrodsburg was named the site of the district court. Samuel was designated one of three district judges for Kentucky. When the first session was held, the court met at the "Dutch Meeting House," located about six miles from Harrodsburg. In order to have a more prominent place to hold court and a location for a jail, the court asked Walker Daniel, prosecuting attorney for the district court, and John May to establish a site near John Crow's station. The buildings were constructed and the settlement was named Danville, in honor of Walker Daniel. McDowell was an original trustee of the town, a fact which induced Fackler to call him the town's first citizen.