William Downing was born in Virginia in about 1680 and emigrated to North Carolina by 1715, settling in Chowan Precinct. In 1724 he became as associate justice of the North Carolina General Court, serving until 1727. He also represented Chowan in the North Carolina General Assembly from 1725 to 1735, in which role he primarily concerned himself with the colony's financials. In 1735 he became the colony's treasurer for the northern district. He later represented Tyrrell County in the assembly and died on April 1, 1739.