Nast was married twice. His wives were:
*
(Jeanne) Clarisse Coudert (later Mrs. J.V. Onativia), a
Coudert Brothers law-firm heiress who became a set and costume designer. Married in 1902, separated in 1919, and divorced in 1923, they had two children, Charles Coudert Nast and Natica Nast. (See
photographs of Clarisse Nast on Wikimedia Commons.)
*Leslie Foster (later Lady Benson), whom he married in 1928; a granddaughter of Gov. George White Baxter of Tennessee, the bride was 20, the groom was 55. Divorced in the early 1930s, they had one child, a daughter, Leslie (who married firstly, Peter George Grenfell, 2nd
Baron St. Just, and secondly,
Lord Bonham Carter).
Between 1932 and 1936, Nast's companion was the
Vanity Fair writer Helen Brown Norden, author of
The Hussy's Handbook (1942).