Born and raised in Toronto, Ontario, Mike Pelyk spent most of his early hockey career playing in the Greater Toronto Area. A product of the Toronto Marlboros of the Ontario Hockey Association, Pelyk was an integral member of the Marlboros' 1967 Memorial Cup winning club which was coached by former Leaf, Gus Bodnar. Originally, Pelyk was the Leafs' third selection, 17th overall, in the 1964 NHL Draft.
Pelyk made his NHL debut when the Leafs took on the Blackhawks at Chicago Stadium on February 7, 1968. He appeared in 23 more games in his rookie season of 1967-68. Over the following six seasons, Pelyk surpassed the 70-games played mark three times.
A gifted skater, the defenceman's best scoring season came in 1973-74 when he earned 12 goals and 19 assists for 31 points in 71 games. The 12 goals were only surpassed on the Leafs' blueline by Jim McKenny (14) and the defensive corps also included offensive stalwarts Borje Salming and Ian Turnbull. He jumped to the World Hockey Association in July 1974 and played in the rival league for two seasons (150 games) before reuniting with the Leafs in 1976-77. His final game in the Blue and White came on April 9, 1978 at Buffalo after splitting his last two seasons between the Leafs and their affiliates in the Central Hockey League.
In 441 games over two tenures with Leafs, Pelyk recorded 26 goals, 88 assists, 114 points and 566 penalty minutes.
Pelyk held the title of President of the Toronto Maple Leafs Alumni Association for many years beginning in 2003 and hold the role of Chairman of the NHL Alumni.