Plett didn't start playing organized hockey until age 12 although once he caught on, he fell in love with the game. But by the time he made the junior level with the St. Catharines Blackhawks of the OHA, he lacked finesse and aggressiveness. As a result, his coach, Hap Emms, demoted him to a tier-two level club.
From that point forward, Plett began to barge around the ice, playing roughhouse hockey. It didn't do too much to raise his stock in the draft, but the Atlanta Flames eventually picked him up in the 4th round in 1975.
Plett tried his hand with the Flames for a couple of games before heading to Tulsa for tutelage from a coach who could understand his needs, former NHL enforcer Orland Kurtenbach.
The following season, Plett started the year in Tulsa, but then got the call to join the Flames where he made a surprise splash, netting 33 goals in 64 games. By season's end, he had secured the Calder Trophy as the league's best rookie.
Clearly Willi Plett was a big, tough player who thrived on aggressiveness and fighting. But he brought much more to the rink than a set of brass knuckles. He could play the game. In 1980-81, with the Calgary Flames, Plett scored a career-high 38 goals.
But not long after his transition to the Minnesota North Stars, in 1982-83, his role was changed from a bellicose goal scorer to exclusively that of a pugilist. As a result his point production fell way off and as he approached age 30, he simply lost the desire to strut around the rink talking tough and fighting. He noted that as he got older, it was as though he became too mature to act that stupid.
In 1987, the Bruins picked him up in the Waiver Draft. With a lineup replete with tough guys, Plett was finally able to assume a role as a support player. With his former nemesis, Terry O'Reilly as coach, Plett enjoyed team leadership that understood his situation as the aging gunslinger. As such, the Bruins made a solid run in the playoffs, making it to the finals, only to be shut out by the Edmonton Oilers. It was Plett's final game in the NHL.