In 1947, she established the Richard C. du Pont Memorial Trophy to be awarded annually to the United States National Open Class Soaring Champion.
Always a lover of animals, Allaire du Pont operated Woodstock Farm in Chesapeake City, Maryland and raced under the nom de course Bohemia Stable.
Following the death of E. P. Taylor in 1989, Allaire du Pont was instrumental in having 2,500 acres (10 km2) of his property go into permanent preservation rather than be sub-divided into building lots by real estate developers.
Du Pont was also a co-founder and member of the board of directors of Thoroughbred Charities of America, an organization whose activities include raising funds to save retired horses.
Among the other charitable causes to which she devoted both time and money were Paws for Life, Mid-Atlantic Horse Rescue, Greener Pastures, and the Union Hospital, of which she was an honorary member of the board of directors.