From 1946 until the 1980–81 season, the Vezina Trophy was awarded to the goaltender(s) of the team allowing the fewest number of goals during the regular season. However, it was recognized that this system often meant the trophy went to the goaltender of the better team rather than the individual and hence the change was made to offer the Vezina to the most outstanding goaltender, as voted by the NHL General Managers. The William M. Jennings Trophy was created as a replacement and is awarded to the goaltender(s) playing for the team with the fewest goals against.
The Jennings Trophy was donated by the NHL's board of governors and first presented at the conclusion of the 1981–82 season. It is named in honor of the late William M. Jennings, who was a longtime governor and president of the New York Rangers and a builder of ice hockey in the United States. Normally the minimum number of games a goaltender must play to be eligible for the trophy is 25, but for the lockout shortened 1994–95 season, the required minimum was fourteen games.
Six players have managed to win both the Jennings and Vezina Trophy for the same season: Patrick Roy (1988–89 and 1991–92), Ed Belfour (1990–91 and 1992–93), Dominik Hasek (1993–94 and 2000–01), Martin Brodeur (2002–03, 2003–04), Miikka Kiprusoff (2005–06) and Tim Thomas (2008–09). Roy and Brodeur have each won the trophy five times, the most of any goaltenders. Belfour is second, having won the trophy four times. It has been won most often by the Montreal Canadiens and the New Jersey Devils, with each team winning the award 5 times. The Chicago Blackhawks have four wins, and the Buffalo Sabres have three wins.