Additionally, McCreery was chief of staff at Greenwich Hospital (Connecticut) from 1939 to 1948, and one of the founders of the American Board of Surgery.
His mother was a daughter of Andrew Carrigan (1804-1872), a wealthy Irish-born philanthropist and provisions dealer who co-founded the Emigrant Savings Bank.
It was there in 1918 that he met Miss Eileen Birkett Ravenshaw of England, an ambulance driver stationed in France as well.
McCreery started off as a private physician in New York City, however later took a position as chief of surgery at Bellevue Hospital Center during the early 1920s.
After moving to Greenwich, Connecticut in 1931, the McCreery family resided at an English estate in the Khakum Wood section known as "Quiet Waters"; the house is currently owned by former U.S.
He was survived by his wife, Eileen Ravenshaw McCreery; three daughters, Joan (Mrs. John Wynne Gerster), Lalande (Mrs. John William Keeshan), and Sheila (Mrs. Richard Newton Jackson, Jr.); and two sisters, Christine (Mrs. Ramsay Charles Hoguet) and Mary McCreery.