The team announced the signing Wednesday, two days before LaRose was due to become an unrestricted free agent.
LaRose will make $1.5 million this season and $1.9 million in 2012-13. The popular right winger made $1.9 million last season.
General manager Jim Rutherford calls LaRose "one of my favourite players" and says he hopes he is "a lifelong player with the organization."
LaRose had 16 goals and 15 assists last season while matching his career high with 31 points.