Incumbent Republican governor Arthur B. Langlie declined to run for a fourth term, instead challenging Warren Magnuson for a U.S. Senate seat.

[1] Langlie made no public endorsement for a Republican candidate, but privately supported congressman Thor C. Tollefson prior to the announcement.

[2] Tollefson would later drop out of the gubernatorial race by the end of the month and pursue another congressional term, leaving Lieutenant Governor Emmett T. Anderson and Attorney General Don Eastvold as the remaining Republican frontrunners.

[7] Prior to the primary, Anderson emerged as a Republican favorite among former Langlie supporters, while Democrats Coe and Rosellini were expected to split a contentious vote.

[9] Coe formally endorsed Rosellini on September 26, citing a preference to avoid "past stalemates" and encouraging voters to give majority control of the legislature to the Democrats.