Kimmo played over 1,100 games spanning 16 seasons in the NHL for the Nashville Predators, Philadelphia Flyers, and Chicago Blackhawks. During his career, Kimmo also participated in three IIHF World Junior Championships, seven IIHF World Championships, two World Cups and five Olympic tournaments.
The Los Angeles Kings drafted Kimmo in the tenth round, 250th overall, of the 1993 NHL Entry Draft. The Kings traded Kimmo to the Nashville Predators before the start of the 1998-99 season. On October 3, 2006 Kimmo was named captain of the Nashville Predators.
Following the 2006-07 season, the Predators traded Kimmo to the Philadelphia Flyers. Shortly after, he signed a six-year, $37.8 million contract extension, a deal which made him the highest paid Finnish player in the NHL.
While preparing for the 2014-15 season, Kimmo was diagnosed with blood clots in both lungs and his right leg. The Flyers traded Kimmo to the Chicago Blackhawks at the 2014-15 trade deadline. On March 5, Kimmo announced his intent to retire from professional hockey after the 2014-15 season. On June 15, Kimmo won his only Stanley Cup with the Blackhawks in the final game of his 20-year professional career.