The native of Scarborough played a year of junior with the Windsor Spitfires of the OHA in 1975-76. The next year he enrolled at Acadia University but didn't suit up for the varsity hockey team until the following season. After leaving school Kotsopoulos spent two years in the minors before he was signed as a free agent by the New York Rangers.

As a rookie in 1980-81, Kotsopoulos recorded 16 points and demonstrated a willingness to play physically in his own end. Before the start of the next season, he was traded to the Hartford Whalers as part of the package assembled to acquire speedy forward Mike Rogers. Kotsopoulos spent four years with the Whalers but, when the team became deep on the blueline in the mid 1980s, he was shipped to the Toronto Maple Leafs for checking forward Stu Gavin.

Kotsopoulos helped to stabilize the Leafs' erratic young defensive brigade and the team reached the second round of the playoffs in 1986 and 1987. When he no longer fit into Toronto's plans, Kotsopoulos signed with the Detroit Red Wings as defensive insurance. After playing only two NHL games in Motown and a handful of AHL contests, he retired in 1990.

Courtesy of the Hockey Hall of Fame