[1] In 1930, amidst the Great Depression, Ladd created the foundation named for her father with $5 million initial endowment (equivalent to $91,195,000 in 2023) to be used for "preventing and curing disease and relieving human suffering.
The foundation funded research and studies on health topics including the process of aging, endocrinology, nutrition, and convalescent care.
In 1943, with the United States fighting in the Pacific theater, the foundation endowed $150,000 to create a five-year research and teaching in program of tropical medicine at the Columbia-Presbyterian Medical Center.
[5] Beginning in 1908, Ladd provided a convalescent facility at “Maple Cottage,” a large residence on her Peapack-Gladstone, New Jersey estate, Natirar, where “deserving gentlewomen who are compelled to depend on their own exertions for support shall be entertained, without charge, for periods of time while convalescing from illness, recuperating from impaired health, or otherwise in need of rest.” [6] Following Ladd's death in 1945, title to Natirar was conveyed to the Kate Macy Ladd Fund, and the convalescent facility was relocated from Maple Cottage to the renovated main residence on the estate.
[6] In 1983, fifty years after Walter Ladd's death and in accordance with his will, Natirar was sold and was purchased by King Hassan II of Morocco.