The Leafs opponent was the Boston Bruins, who finished the season with a 36–10–2 record, earning 74 points, which was 27 points more than the Leafs. The Bruins defeated the New York Rangers 4 games to 3 in the Semi-Finals and went into the series the favorites, sporting new uniforms with gold added to the shoulders, pants and socks.
Game 1 in Boston was a tight-checking affair with Woody Dumart opening the scoring at the 16:04 mark of the first period with the first playoff goal of his career. The Leafs tied it up in the third with the first of the playoffs for Red Horner but less than three minutes later, Bobby Bauer won it for the Bruins.
Game 3 in Toronto was scoreless in the second period when Eddie Shore checked Leafs star Busher Jackson, dislocating his shoulder. Jackson missed the remainder of the series. Disheartened, the Leafs gave up goals by Bauer, Conacher and defenseman Jack Crawford (first playoff goal of his career). A last minute goal by the Leafs Gus Marker wasn't enough as the Bruins won 3-1.
Game 4 in Toronto saw the Bruins go ahead 1-0 early in the game on a power play goal by Conacher, assisted by Hill. The Bruins Frank Brimsek shut the door and earned his first playoff shutout as the Bruins won 2-0 after Conacher added his second of the game.
Game 5 in Boston saw Hill score his 6th of the playoffs at 11:40 of the first period while Gord Drillon was in the penalty box. Toronto countered with a power play marker of their own when Kampman scored at 18:40 on a point shot, that deflected off Dit Clapper's skate, with Hill in the box. With the score tied 1-1 late in the second period, Conacher broke in on a breakaway and fired the puck over Broda's left shoulder, his 6th goal of the playoffs. This put the Bruins up 2-1, which would prove to be the winner. The Leafs frantically tried to tie it up in the third and had a perfect opportunity when Eddie Shore took a penalty with 2 minutes to go. However, the Leafs Nick Metz, who'd been called up as Busher Jackson's replacement, took a penalty and the teams skated four on four. With 37 seconds left, Flash Hollett widened Boston's lead to 3-1. The Bruins took the series and the Cup 4 games to 1. Frank Brimsek held Toronto to just six goals in five games. Bill Cowley led the playoffs in scoring with 11 assists and 14 points.