The Capitals, who were upset by Montreal in the first round of the playoffs last month after compiling the National Hockey League’s best regular-season record, also have Russian playmaker Alex Ovechkin inked to a long-term deal.
Bäckström scored 33 goals and assisted on 68 others to rank fourth in total points in the NHL. Bäckström, 22, has not missed a game in three NHL seasons and would have become a free agent in July.
Ovechkin, a former scoring champion and two-time NHL Most Valuable Player, is about to enter the third season of a 13-year contract worth $124 million.
The deal secures Washington two of the league’s top young stars but could make it difficult to keep other talented teammates, such as Russian standout Alexander Semin, under the NHL’s salary cap rules.