Theresa Maria Clark (née Scheidemantel) also worked as an editor at the firm, and they eventually married.
In 1938 Hugh and Theresa purchased the firm, sold off the retail postage stamp and coin sales portions of the business, and renamed it Scott Publications.
Hugh Clark was active in promoting stamp collecting through various media, including radio, newspapers, advertising, and lending frames to philatelists for use at philatelic exhibitions.
In 1947 Hugh Clark signed the Roll of Distinguished Philatelists,[1] and, he was named to the American Philatelic Society Hall of Fame in 1957.
When the Clarks sold Scott Publications, they donated its famous reference collection, originally constructed by John Nicholas Luff, to the Philatelic Foundation.