William Henry Fitzhugh was born at Chatham, in Stafford County, Virginia.

William Henry Fitzhugh married Anna Maria Sarah Goldsborough (1796–1874), daughter of prominent Maryland lawyer and politician Charles Goldsborough, who survived him, but the couple had no children.

[7] Fitzhugh's last legislative service was at the Virginia constitutional convention of 1829–1830, where he joined Richard R. Henderson, Charles Fenton Mercer, and James Monroe in representing the district comprising Fairfax and Loudoun Counties.

[8] His widow survived the American Civil War; she then bequeathed most of her property to children of CSA General Robert E. Lee (Mary Randolph Custis' husband).

Both William Henry Fitzhugh and his wife are now buried in the cemetery of historic Pohick Church in Lorton.