Born in Warren County, North Carolina, William Miller was orphaned at the age of 9 and inherited a substantial plantation.

He briefly attended the University of North Carolina at Chapel Hill in 1802, but did not complete a degree.

In November 1814, Miller was elected Governor of North Carolina by the General Assembly, at the close of the War of 1812, which he supported.

During his term, Miller laid the groundwork for the expansion of the state's educational system, and he served on the University of North Carolina Board of Trustees until his death.

After serving the maximum number of three one-year terms as governor, Miller left office in 1817.