He was a son of Frederick Theodore Frelinghuysen and Matilda Elizabeth Griswold (who was of English descent).

[b] Both grandfather and adopted grandfather were sons of Frederick Frelinghuysen, the eminent lawyer who was one of the framers of the first New Jersey Constitution, a soldier in the American Revolutionary War, a member of the Continental Congress, and a member of the United States Senate.

[14] His maternal grandfather George Griswold,[3] was a merchant in New York City who "made an immense fortune in the time of the clipper trade with China.

[17] Her paternal grandfather was Chargé d'Affaires to the Kingdom of Sardinia William Burnet Kinney (whose second wife was writer Elizabeth Clementine Stedman).

Together, they lived in Elberon, New Jersey, and were the parents of four sons and one daughter including:[3] He died in the Post Graduate Hospital after a three-week illness in Manhattan, New York City, on January 1, 1924.