The Bruins announced the signing on Wednesday afternoon.
Renaud Lavoie of RDS reported via Twitter that the deal will pay Marchand $2 million in 2011-12 and $3 million in 2012-13. The report was also made by ESPN's Pierre LeBrun and The Fourth Period's David Pagnotta.
Marchand, 23, was a restricted free agent this offseason, but he appeared at team events throughout the summer. Both he and the team expressed confidence that a deal would get done before camp opened this weekend, and it appears as though they've followed through.
Last season, Marchand scored 21 goals and added 20 assists in his rookie campaign before emerging as a young star in the postseason, when he had 11 goals and nine assists in 25 games.