[8] His paternal grandfather was Richard Mortimer, a real estate investor and member of Ward McAllister's "Four Hundred", purported to be an index of New York's best families.
[9][10] Through his father and paternal grandmother, Eleanor Jay Chapman Mortimer, he was a descendant of the first chief justice of the U.S. Supreme Court, John Jay, as well as the first colonial Governor of New York, Robert Livingston[11][8] Mortimer grew up at Keewaydin, the family home in Tuxedo Park designed by Stanford White for Pierre Lorillard III.
According to author Sally Bedell Smith, "her annual debutante dinners before the Autumn Ball determined which young women were approved for New York society.
[15] A renowned sportsman, Mortimer was a member of the Jockey Club, and his racing stable at Keewaydin was successful in France for many years.
Ambassador to Russia and the U.K., a governor of New York and a U.S. Secretary of Commerce under President Harry S. Truman) and a granddaughter of railroad tycoon E. H.
[24] Together, they had a home in Harriman and an apartment at 149 East 73rd Street in Manhattan,[25] and were the parents of three children:[15] In 1969, Mortimer, who suffered from manic-depression, shot himself in what may have been a suicide attempt,[25] but survived.