Like his father, Thomas, who played for the Winnipeg Jets from 1981-95, Steen began his NHL career with a Canadian team when he debuted for the Toronto Maple Leafs on Oct. 5, 2005, against the Ottawa Senators. When Steen had a goal against the Montreal Canadiens in his second NHL game three days later, he and his dad became the first Sweden-born father-son combination to score in the NHL.
The Maple Leafs selected Steen in the first round (No. 24) in the 2002 NHL Draft. He represented Sweden at the 2002 World Under-18 Championship and at the World Junior Championship in 2003 and 2004. Steen scored 18 goals as an NHL rookie in 2005-06 and had at least 15 goals in each of his first three seasons.