The Association split its hockey operations, relocating the NHL franchise to St. Louis, and continuing the Senators as an amateur club.

The club operated from 1934 until 1955, winning the Allan Cup Canadian men's senior ice hockey championship in 1943 and 1949.

[1][3] The 'Senior Senators' took over the 'barber-pole' striped sweaters with the 'O' logo, and played in the same home arena, the Auditorium, but in an amateur league.

During this time, NHL players who had enlisted in the Canadian armed forces, continued to play hockey in senior leagues.

The Commandos had players such as goaltender Jim Henry of the New York Rangers, whose military posting was in Ottawa.

During its history the club's owners included James MacCaffrey, who was also its first manager, and who owned the football Ottawa Rough Riders and Tommy Gorman, who had had a partial ownership of the Senators previously from 1917 until 1925, and had gone on to be an NHL executive with the Chicago Black Hawks, New York Americans, Montreal Maroons and Montreal Canadiens.

[5] The Senators joined the 'Montreal Group' and played against six teams from the Montreal area: McGill, "Jr." Canadiens, Lafontaine, Royals, Verdun and Victorias.

In the finals against the Montreal Royals, Ottawa lost three straight ( 2-3, 1-2(OT), 1-5) to lose the series.

Former Ottawa Citizen sports editor Tommy Shields took over as coach this season.

His first season as coach was unsuccessful as Ottawa finished out of the playoffs, placing fifth in the group.

The team bounced back this season to finish first in the group with new coach Gene Chouinard.

Ottawa faced the Cornwall Flyers in the semi-finals, and defeated them in a best-of-five 3-0-1 ( 5-0, 5-5, 1-0 and 3-2 ) to advance to the finals.

[11] In 1947, the club was bought by Tommy Gorman, who had returned to Ottawa and was promoting sports including boxing and horse racing in the capital.

The first was the Ottawa Nationals which played in the WHA's 1972–73 inaugural season before relocating to Toronto.