Vern Countryman was born in Roundup, Montana.
On November 9, 1940, he married Vera Marie Pound (July 19, 1917 - December 2, 1994), a daughter of former Harvard Law School Dean Roscoe Pound (October 27, 1870 - June 30, 1964), with whom he had two daughters: Debra Green and Kay Briggs.