In his first season he recorded 20 goals and 25 assists for 45 points which earned him the Calder Trophy for Rookie of the Year. The one thing that stands out about Keon's entire career is his lack of penalties. In 18 seasons with the NHL, Keon recorded only 117 minutes in penalties, and in four seasons with the WHA he only had 20 minutes. In 13 Playoff seasons he had only 6 minutes in penalties. It's no wonder that some of Keon's awards centre around the Lady Byng which he won twice(1962 and 1963) and the WHA equivalent, the Paul Daneau Trophy which he won in 1977 and again in 1978.

Keon earned the Conn Smythe Trophy in the 1967 Playoffs when Toronto defeated the Montreal Canadians and Keon notched 3 goals and 5 assists. Red Fisher remarked, "I don't know any player who did as much damage to the Montreal Canadiens as Dave Keon." This was the last Stanley Cup to be won under the Original Six format.

In 1969-70 Keon succeeded George Armstrong for the captaincy and steadily improved his performance until the 1970-71 season when he turned in his best performance with 38 goals and 38 assists for 76 points. After 15 years in the NHL, Keon jumped to the World Hockey Association and had brief stints with the Minnesota Fighting Saints, The Indianapolis Racers and the New England Racers from 1975-76 to 1978-79. During his 301 games he had 102 goals and 189 assists and 20 minutes in penalties.

In 1979-80 Keon returned to NHL action with the Hartford Whalers for 3 seasons, when in 1982 Dave hung up the blades for good. He was elected to the Hockey Hall of Fame in 1986.