Bennett, 42, directed the Gaels to a 25-9 record and just the fourth NCAA Tournament berth in school history. Four years after taking over a program that was 2-27 in 2000-01, Bennett has compiled a record of 68-56.
Sustaining basketball success has been troublesome at St. Mary's, which lost coaches to more lucrative Pac-10 Conference jobs after its two previous NCAA trips, in 1997 and 1989.
"As far as making a commitment to the school, that was a no-brainer for me," Bennett said. "The success of our program is a positive, and I look forward to the challenge of sustaining it, which really hasn't ever been done here for an extended period of time.
"I think it can be done. Our program has created an excitement of, 'Let's try to do this on a regular basis.'"
The Gaels lose four senior starters from the team that tied a school record for victories in a season, but athletic director Carl Clapp expressed optimism about the program's future.
"I think it's great for St. Mary's," Clapp said. "It says a lot about the college's commitment to the athletic program and the men's basketball program. I believe that continuity in coaching is vitally important to building programs and creating success."