The restricted free agent, the team's No. 1 center, will earn an average of $5.25 million per year.
Benn missed last's week training camp and the opening week of the NHL season while negotiating a new deal.
The 23-year-old native of Victoria, British Columbia, was second on the team in scoring last season with 63 points (26-37) in 71 games.
Information from ESPN.com's Pierre LeBrun was used in this report.