On August 15, 1778, Tatom enlisted as assistant quartermaster and keeper of the arsenal in the State service at Hillsborough, North Carolina; he was contractor for Hillsborough in 1778 and named major of detachment of the North Carolina Light Horse February 12, 1779.
Tatom rose in state government; in 1782, he was one of three commissioners appointed by Congress to survey lands granted to Continental soldiers in the western territory (later Tennessee); that same year, he was a private secretary of Governor Thomas Burke and state tobacco agent.
In 1788, Tatom was a delegate to the convention which considered ratification of the United States Constitution.
In 1794, Tatom was elected as a Democratic-Republican to the 4th United States Congress where he served from March 4, 1795, until his resignation on June 1, 1796.
Tatom was later a member of the state House of Commons from 1797 to 1802; he died in Raleigh, North Carolina, in December 1802 and is buried in the Old City Cemetery.