The Ducks announced they had signed the 38-year-old forward on Friday, after the start of the NHL's free-agency period. Koivu is a 17-year NHL veteran, who returns for a fifth season in Anaheim.
Koivu had 27 points (eight goals, 19 assists) in 47 games last season, while also breaking the 800-point plateau for his career. Overall, he has 244 goals and 559 assists in 1,058 career games.
He spent his first 13 seasons with Montreal, after being selected in the first round (21st overall) in the 1993 draft.