Oliver Wolcott was born at Windsor, Connecticut, on November 20, 1726, under the Old Style calendar then used in the British colonies, corresponding to December 1 under the later New Style reckoning. He was one of the many children of Roger Wolcott and Sarah Drake Wolcott. His father rose from trade and militia service to become governor of Connecticut, giving Oliver an upbringing shaped by public office, Congregational religion, farming, and the colony’s unusually strong tradition of local self-government.

Wolcott attended Yale College and graduated in 1747. Yale’s curriculum emphasized classical languages, logic, rhetoric, theology, mathematics, and moral philosophy. His education prepared him for civil administration and the learned professions, but events directed him first toward the military. Immediately after graduation, New York governor George Clinton commissioned the twenty-year-old Wolcott as a captain for service on the northern frontier during King George’s War.

The young officer raised or commanded men defending the borderlands against French forces and their Indigenous allies. Frontier duty taught him logistics, militia organization, diplomacy, endurance, and the difficulties of coordinating provincial defense. The war ended in 1748 before he established a permanent military profession. Wolcott then returned to Connecticut and studied medicine for a time with his brother, Dr. Alexander Wolcott. Although he acquired medical knowledge, he did not build his principal career as a physician.

In 1751 Wolcott moved to the newer inland town of Litchfield, where his father owned property. He entered local public service as the town’s first sheriff and began managing land and community affairs. In 1755 he married Lorraine Collins; their family eventually included Oliver Wolcott Jr., later secretary of the treasury and governor of Connecticut.