The club was the first hockey club in Ontario, a founding member of the National Hockey League (NHL) and played in the NHL from 1917 until 1934. The club, which was officially the Ottawa Hockey Club (Ottawa HC), was known by several nicknames, including the Generals in the 1890s, the Silver Seven from 1903 to 1907 and the Senators dating from 1908.
Generally acknowledged by hockey historians as one of the greatest teams of the early days of the sport, the club won numerous championships, starting with the 1891 to 1893 Ontario championships. Ottawa HC played in the first season during which the Stanley Cup was challenged in 1893, and first won the Cup in 1903, holding the championship until 1906 (the Silver Seven years). The club repeated its success in the 1920s, winning the Stanley Cup in 1920, 1921, 1923 and 1927 (the Super Six years). In total, the club won the Stanley Cup 11 times, including challenges during two years it did not win the Cup for the season. In 1950, Canadian sports editors selected the Ottawa HC/Senators as Canada's greatest team in the first half of the 20th century.
The club was one of the first organized clubs in the early days of the sport of ice hockey, playing in the Montreal Winter Carnival ice hockey tournaments in the early 1880s and founding the Amateur Hockey Association of Canada and the Ontario Hockey Association. Along with the rise of professionalism in ice hockey in the first decade of the 1900s, the club changed to a professional team and were founding members of the National Hockey Association (NHA) and its successor, the National Hockey League. The club competed in the NHL until the 1933–34 season. Due to financial difficulties, the NHL franchise relocated to St. Louis, Missouri to become the St. Louis Eagles. The organization continued the Senators as an amateur, and later semi-professional, team in Quebec senior men's leagues until 1954. The "Senior Senators" would win three Allan Cup titles.