Helenius was drafted by the Calgary Flames as their fifth-round pick, 102nd overall, in the 1992 NHL Entry Draft. He started his professional career in Jokerit in the Finnish SM-liiga in 1992, and made his way to North America for the 1994–95 season, and after spending five years mostly in the minor leagues, Helenius took his place as an NHL defenceman, playing for several teams. Helenius became known as the "Fighting Finn," as he was one of the few Europeans to play in an enforcer role in North-American hockey leagues.