Kent Douglas began his career as a hockey player in the Ontario Hockey Association, where he was active from 1954 to 1957 for the Kitchener Canucks and the Owen Sound Mercurys. During this time he made his debut in professional ice hockey in the 1955/56 season, when he was on the ice in three games for the Springfield Indians from the American Hockey League , in which he scored one goal. After two years in the Western Hockey League with the Winnipeg Warriors and the Vancouver Canucks , the defender returned to the Springfield Indians towards the end of the 1958/59 season, with whom he won the Calder Cup three times in a row in 1960, 1961 and 1962 . Then the Toronto Maple Leafs from the National Hockey League signed the left-handed shooter, with whom he won the prestigious Stanley Cup three times (1963, 1964 and 1967) five seasons , his name being engraved only the first time on the cup itself, as he was summoned to Toronto's farm teams before the playoffs . In the 1962/63 season, Douglas also received the Calder Memorial Trophy as rookie of the year in the NHL.
In the 1967/68 season, the Canadian was under contract with Toronto's league rivals Oakland Seals , but ended the season with the Detroit Red Wings , for which he ran up a total of one and a half years in the NHL. There followed three seasons in the AHL with the Rochester Americans and the Baltimore Clippers , before the former NHL player was signed by the New York Raiders from the newly founded World Hockey Association in the summer of 1972 , for which he then scored a total of 18 points in 60 games, including three goals, scored. The man from Ontario finally ended his active career in 1976 with the Baltimore Clippers in the AHL, for which he was active as an assistant coach in addition to his position as a player from the 1974/75 season. In addition, Douglas played in the 1974/75 season for the Toledo Goaldiggers from the International Hockey League , with whom he won the Turner Cup .