Kruger, 25, had left wrist surgery in December but is expected to return before the start of the playoffs. He will make $3,475,000 in each of the next two years and $2.3 million in the final season.
Kruger signed a one-year deal before this season.
A fifth-round pick in the 2009 draft, he made his NHL debut in 2011 and has developed into a versatile performer who helps kill penalties and often draws difficult defensive assignments. He had seven goals and 10 assists in 81 games last season and then helped Chicago win the Stanley Cup for the third time in the past six seasons.
Kruger has 28 goals and 57 assists in 320 career games, all with Chicago.