The Ottawa Senators won the first Stanley Cup awarded after the trophy became an NHL championship in 1927.
Ottawa defeated the Boston Bruins in the 1927 Stanley Cup Final, winning the best-of-five series three games to two. The championship was the Senators’ fourth Stanley Cup and the last won by the original Ottawa NHL franchise.
The 1927 Final marked an important structural change because the Stanley Cup became the championship trophy of the NHL alone. Before that season, teams from other leagues and associations could compete for it under interleague arrangements. The NHL had become the only league eligible to award the Cup after the Western Hockey League folded.
This milestone is different from the first Stanley Cup in 1893, which was won by the Montreal Hockey Club under the earlier challenge system. Ottawa’s 1927 title began the modern NHL-only era of the championship.