1938–39 NHL season

League business

Before the season, the NHL rejected the Montreal Maroons' request to move to St. Louis, so the team shut down and sold most of its players to the Canadiens. This was the last time a past Stanley Cup winner folded or moved. With only seven teams left, the league went back to a single division. The Stanley Cup Final became a best-of-seven series. In August 1938, NHL president Frank Calder made a new deal with the Canadian Amateur Hockey Association and its president W. G. Hardy. This agreement limited how many amateurs could be signed and made both sides use the same rules and honor each other's suspensions.

Regular season

Before the season, the Boston Bruins sold star goaltender Tiny Thompson, a four-time Vezina Trophy winner, to the Detroit Red Wings. Rookie Frank Brimsek replaced him, recording three consecutive shutouts to break Thompson's shutout sequence record, then nearly matched it with three more. Brimsek finished with 10 shutouts, earned the nickname "Mr. Zero," and became the first goaltender to win both the Vezina Trophy and Calder Memorial Trophy in the same season.

Joseph Cattarinich, original goaltender of the Montreal Canadiens and later a part-owner, died on December 7 of a heart attack following an eye operation at age 57. The Canadiens struggled, with Jules Dugal replacing Cecil Hart as manager and coach; they finished sixth, though Toe Blake won the scoring title. The New York Americans, in third place at mid-season, slumped in the second half to finish fourth below .500 with the league's worst defence, partly due to retirements of Ching Johnson and Hap Day; goaltender Earl Robertson made the second all-star team.

Playoffs

With seven teams, a new playoff format was adopted, using a double-elimination-style structure with a winners' bracket and a repechage bracket. The top six teams qualified; the top two played a best-of-seven semifinal, while the third and fourth met in a best-of-five series, and the fifth and sixth in another best-of-five. The semifinal winners then met in a best-of-seven Stanley Cup Final. This series was the first in NHL history to need seven games; the Rangers were the first team to force a Game seven after losing the first three games. Mel Hill of the Bruins scored a record three overtime goals in a single series.