Since his family traveled widely, he attended 12 different schools before enrolling in the Bolles School in Florida, where he graduated as an outstanding cadet. While earning a degree in sociology at Princeton, he was known to skip lunches to sit in on other classes.

After four years at the Ohio State University College of Medicine and an internship at Pittsburgh’s Shadyside Hospital, Duff completed his psychiatric training at the Menninger Clinic in Topeka, Kan. Following service as a base psychiatrist at Bainbridge Naval Training Center in Maryland, he set up a private practice in Painesville, Ohio, likely the first mental health professional to practice in the area. He subsequently moved to Defiance, Ohio, and finally ended his 55 years of practice in Kokomo.

Duff was an accomplished woodworker, furniture maker, and sailor. Of his Princeton days, it was reported in his obituary that his only regret was that as he walked past Albert Einstein on campus, he failed to ask, “Who cuts your hair?”

Alice, whom he married in 1954, predeceased him. Three sons, Anders, Stephen, and Alec, and two granddaughters survive him.