From 1927–28 onwards, one year after the NHL expanded to two divisions in 1926, the Cup was awarded to the winner of the Canadian Division, while the Prince of Wales Trophy was awarded to the winner of the American Division. It would be awarded under this definition until the end of the 1937–38 season.
The 1938–39 NHL season saw the NHL move back to a single division, and from that point on the Cup was awarded to the Stanley Cup runner-up. The O'Brien Cup was not formally awarded from 1939 to 1943 and it would not be until 1944 that the winning teams from that period were inscribed on the Cup. At the end of the 1949–50 NHL season the Cup was retired and has not been awarded since. It is now in the collection of the Hockey Hall of Fame in Toronto, Ontario and is on display with other historic trophies in the entrance to the Panasonic Hometown Hockey exhibit.
The Montreal Canadiens have won it the most, having won the trophy 10 times. The Toronto Maple Leafs have won it the second most, a total of nine times, seven as the Maple Leafs, once as the St. Patricks and once as the Torontos. The Detroit Red Wings have won the trophy the most times of any American team, having won it five times.
| Wins | Team |
|---|---|
| 9 | Toronto Maple Leafs (7 wins) St. Patricks (1 win) Toronto1 (1 win) |
| 8 | Montreal Canadiens |
| 5 | Detroit Red Wings |
| Ottawa Senators | |
| 2 | Quebec Bulldogs |
| Montreal Maroons | |
| Boston Bruins | |
| 1 | Chicago Black Hawks |
| New York Rangers | |
| Toronto Blueshirts |
| Winner | Win # | |
|---|---|---|
| 1910 | Montreal Wanderers * ^ | 1 |
| 1911 | Ottawa Senators * | 1 |
| 1911–12 | Quebec Bulldogs * ^ | 1 |
| 1912–13 | Quebec Bulldogs * ^ | 2 |
| 1913–14 | Toronto Blueshirts * ^ | 1 |
| 1914–15 | Ottawa Senators * | 2 |
| 1915–16 | Montreal Canadiens ^ | 1 |
| 1916–17 | Montreal Canadiens | 2 |
| Winner | Win # | |
|---|---|---|
| 1917–18 | Toronto1 | 1 |
| 1918–19 | Montreal Canadiens | 3 |
| 1919–20 | Ottawa Senators * ^ | 3 |
| 1920–21 | Ottawa Senators * ^ | 4 |
| 1921–22 | Toronto St. Patricks ^ | 2 |
| 1922–23 | Ottawa Senators * ^ | 5 |
| Winner | Win # | |
|---|---|---|
| 1927–28 | Toronto Maple Leafs | 3 |
| 1928–29 | Montreal Canadiens | 6 |
| 1929–30 | Montreal Maroons * ^ | 1 |
| 1930–31 | Montreal Canadiens ^ | 7 |
| 1931–32 | Montreal Canadiens | 8 |
| 1932–33 | Toronto Maple Leafs | 4 |
| 1933–34 | Toronto Maple Leafs | 5 |
| 1934–35 | Toronto Maple Leafs | 6 |
| 1935–36 | Montreal Maroons * | 2 |
| 1936–37 | Montreal Canadiens | 9 |
| 1937–38 | Toronto Maple Leafs | 7 |