Originally the championship trophy of the National Hockey Association, the trophy was taken over by the National Hockey League and awarded to the league champions. Upon the donation of the Prince of Wales Trophy to the NHL in the early 1920's, a decision was made by the league executive to retire the O'Brien Trophy. However in 1928, the O'Brien Trophy officially was awarded to the Canadian team with the most points. The significance of the O'Brien Trophy was again altered in 1939, when it became the award handed out to the losing Stanley Cup finalist. The trophy was officially retired by the NHL at the end of the 1949-50 season.
| Year | Winner(s) |
|---|---|
| 1950 | Montreal Canadiens |
| 1949 | Boston Bruins |
| 1948 | Detroit Red Wings |
| 1947 | Toronto Maple Leafs |
| 1946 | Boston Bruins |
| 1945 | Detroit Red Wings |
| 1944 | Detroit Red Wings |
| 1943 | Boston Bruins |
| 1942 | Toronto Maple Leafs |
| 1941 | Toronto Maple Leafs |
| 1940 | New York Rangers |
| 1939 | New York Rangers |
| 1938 | Toronto Maple Leafs |
| 1937 | Montreal Canadiens |
| 1936 | Montreal Maroons |
| 1935 | Toronto Maple Leafs |
| 1934 | Toronto Maple Leafs |
| 1933 | Toronto Maple Leafs |
| 1932 | Montreal Canadiens |
| 1931 | Montreal Canadiens |
| 1930 | Montreal Maroons |
| 1929 | Montreal Canadiens |
| 1928 | Montreal Canadiens |
| 1923 | Ottawa Senators |
| 1922 | Toronto St. Pats |
| 1921 | Ottawa Senators |
| 1920 | Ottawa Silver Seven |
| 1919 | Montreal Canadiens |
| 1918 | Toronto Arenas |
| 1917 | Montreal Canadiens |
| 1916 | Montreal Canadiens |
| 1915 | Ottawa Senators |
| 1914 | Toronto Blueshirts |
| 1913 | Quebec Bulldogs |
| 1912 | Quebec Bulldogs |
| 1911 | Ottawa Senators |
| 1910 | Montreal Wanderers |
