Oliver Wolcott Jr. began public financial work in Connecticut, serving as a state comptroller before joining the new federal Treasury in 1789. As auditor he helped establish its forms and accounting methods; as comptroller from 1791 he worked within the system Alexander Hamilton built for collecting revenue, managing debt and operating the First Bank of the United States. Washington appointed him secretary of the Treasury in 1795, and he continued under John Adams.

Wolcott retained Hamilton's confidence and frequently sought his advice. He faced demands for revenue during the expanding government's confrontation with France, while critics led by Albert Gallatin pressed for closer congressional supervision of Treasury policy. He resigned at the end of 1800 and invited an investigation that cleared his administration the following year. Adams then appointed him a federal circuit judge, but Congress abolished the new circuit offices in 1802.

Wolcott turned to commerce and banking in New York before returning to Connecticut politics. Elected governor in 1817 with support from the Toleration coalition, he presided over the transition from the colonial charter to the state constitution of 1818. The change broadened political participation and ended the established position of the Congregational churches. He remained governor until 1827, serving ten annual terms. His later years were spent outside office, and he died in New York in 1833 after decades in business and public office.