On 30 October 1753 he married Dorothy Willing, the daughter of Charles Willing, a Philadelphia merchant.
Byrd III eventually fathered five children by his first wife (Eliza Carter, m. 1748, d. 1760), and fathered ten more by his second wife, Mary Willing, daughter of Charles Willing of Philadelphia.
Charles Darwin | Charles Dickens | Charles, Prince of Wales | Ray Charles | Charles II of England | Charles I of England | Charles Lindbergh | Charles de Gaulle | Charles II | Charles | Charles I | Prince Charles | Charles V | Charles Scribner's Sons | Charles Aznavour | Charles University in Prague | Charles Stanley | Charles Bukowski | Charles Mingus | Charles Ives | Charles Bronson | Charles Babbage | Charles III of Spain | Charles Cornwallis, 1st Marquess Cornwallis | Charles Baudelaire | Charles Sanders Peirce | Charles River | Charles Manson | Charles Laughton | Charles Dutoit |
Her father, Charles Willing, was the mayor of Philadelphia, Pennsylvania, from 1748 to 1754, and her great-grandfather, Edward Shippen, was the second mayor of Philadelphia from 1701 to 1703.
He would later play Charles Willing in Willing and Abel (1987) in which he co-starred with his former ACP co-star Shane Withington who played the role of Abel Moore.