Suffering from a nervous condition throughout his career, Durnan retired in 1950, citing the stress of playing professional hockey.

Durnan entered the National Hockey League at the age of 27 and played only seven seasons, but accomplished much in his short NHL career.

The Montreal Canadiens fared poorly in 1947–48 and Turk Broda of the Toronto Maple Leafs won it that year instead.

"[1][2] Durnan set a long-standing modern NHL record between February 26 and March 6, 1949, when he registered four consecutive shutouts and did not allow a goal over a span of 309 minutes, 21 seconds.

Durnan retired following the 1949–50 NHL season at the age of 34, being no longer able to stand the stress of playing professional hockey.