Zezel joined the Flyers' lineup in the 1984–85 at the age of 19 and made an instant impact, finishing fifth in rookie scoring with 61 points and setting a team record 46 assists by a rookie. He was part of a young Flyer team (with eight regulars under the age of 22, and only Mark Howe over the age of 27) which surprised the hockey world by reaching the Stanley Cup Finals, where they were defeated by the Edmonton Oilers. The Flyers' head coach at the time was Mike Keenan, who became one of Zezel's biggest influences, and who would re-acquire Zezel several times later in their careers.