The Saskatoon native appeared as a player in just 28 NHL games with the Detroit Red Wings from 1953-55. But it was when he traded in his skates for a suit that Allen made his mark.
Allen joined the Flyers in 1966 and became the franchise's first head coach during its debut season in 1967 when Philadelphia won the West Division title.
He became general manager of the team in 1969 and held the job until 1983. During his tenure the Flyers won back-to-back Stanley Cups in 1973-74 and 1974-75 and reached the Stanley Cup final four times.
Allen's success in turning the Flyers into the "Broad Street Bullies" was built by drafting and acquiring players such as Hall of Famer Bill Barber, Rick MacLeish, Bob Kelly, Bob Clement, Bernie Parent, Barry Ashbee, Reggie Leach, Terry Crisp and Andre Dupont.
"Keith was responsible for the Flyers winning the Stanley Cup," said Hall of Famer Bobby Clarke in a statement. "He was in charge of the draft, in charge of the trades, in charge of getting Bernie back — all the things necessary for us to win the (Cup). He put the pieces in place and hired the coach. He, more than anybody was responsible for us winning the Cups."
Allen was in charge when Philadelphia set a league record 35-game unbeaten streak en route to the Stanley Cup final during the 1979-80 season. Prior to his departure, he drafted players such as Brian Propp, Rick Tocchet and Ron Hextall who would lead the team to two more championship appearances in the '80s.
He also gave the late Fred Shero the head coaching job with the Flyers in 1971, and hired Pat Quinn to his first NHL coaching job in 1978-79.
Allen was elected to the Hockey Hall of Fame as a builder in 1992.
"Keith Allen always found a way to bring exceptional talent to Broad Street and weave it into the fabric of a team that would succeed and endure at the highest level, because in Philadelphia, for his Flyers and their fans, no other level was acceptable," said commissioner Gary Bettman in a statement.
"The National Hockey League sends heartfelt condolences to Keith's family, to his friends and to the Flyers organization, which has lost one of its patriarchs."