Timothy Pickering was born on June 17, 1745, in Salem, Massachusetts, and graduated from Harvard University. He used a law education to begin a career in public service, becoming a selectman and assessor for Essex County, Massachusetts, in 1772.

Soon caught up in the revolutionary fervor of the period, Pickering joined the Committee on the State of Rights of Colonists in 1773 and went on to serve with the Committee of Correspondence and Safety from 1774 to 1775. He accepted an appointment to two Essex County judicial offices in 1775, and by 1776 had gained a seat in the Massachusetts state legislature. His interests tending more toward warfare than politics however, Pickering joined the Revolutionary Army in 1776, applying his experience with the Massachusetts state militia (1766 and 1775). By 1777, Pickering had become adjutant-general and a member of the Continental Congress' Board of War. From 1780 to 1785, he was Quartermaster General of the Army, and he did not retire from military duty until 1788. Involving himself in politics once more, Pickering was amongst those in the Pennsylvania state convention to ratify the U.S. (1787) and state (1790) constitutions. In 1790, President George Washington named him U.S. commissioner to the Seneca Indians and subsequently appointed him to his cabinet as postmaster general (1791-1794).Pickering's stay in cabinet went on to include one year as secretary of war (1795-1796), and five more as secretary of state under both Presidents Washington and John Adams (1796-1800). He would also serve a number of years as a U.S. Senator from Massachusetts (1803-1811 and 1813-1817), and had a brief stay on the Massachusetts executive council as well (1812-1813). Timothy Pickering died on January 29, 1829, in Salem, Massachusetts.