Oliver Wolcott was born in Windsor, Connecticut, the youngest of fourteen children of the Royal Governor Roger Wolcott. He attended Yale College, graduating in 1747. Governor DeWitt Clinton of New York commissioned him to raise a militia to fight in the French and Indian War, and he served the King as Captain in this militia on the northern frontier.
At the end of the war, Wolcott studied medicine, then was appointed sheriff of the newly created Litchfield County, Connecticut, serving from about 1751 to 1771. He then rejoined the Militia and participated in the Revolutionary War as Brigadier General of the Connecticut forces under the command of the Continental Army.
The Continental Congress appointed him Commissioner of Indian Affairs, and he was elected to the Congress in 1775. He became seriously ill in 1776 and did not sign the Declaration of Independence until some time later. He was engaged in military affairs between 1776-8, and served again in Congress from 1778-1784.
He served again as an Indian Commissioner, and was elected Lieutenant Governor of Connecticut in 1786, assuming the Governorship on the death of Samuel Huntington in 1796, and was reelected to the position, dying in office at the age of seventy-one.