RENTON, Wash. -- One-time bust Mike Williams has found a home in Seattle. And instead of testing free agency, Williams decided sticking around with the Seahawks was the better move.

Williams and the Seahawks announced an agreement on a three-year contract extension on Monday. The deal was finalized over the weekend before Seattle beat St. Louis to win the NFC West and become the first sub-.500 division champion in league history.

"I'm happy to be a part of the beginning. I can't really put into words," Williams said. "I'm very blessed."

It's been a banner season for Williams, who spent the previous two years out of the NFL. The former first-round pick finished the regular season with a career-best 65 catches for 751 yards and two touchdowns, including the only TD scored in Sunday night's 16-6 division-clinching win over the Rams.

When Williams arrived in Seattle last April as a free-agent flier, Seahawks coach Pete Carroll seemed to be giving him a chance as a favor to a former USC player; it seemed unlikely this would be the end result.

But Williams proved worthy through his work in the offseason, eventually making Seattle comfortable enough to cut T.J. Houshmandzadeh and make Williams its starting receiver. He quickly became a favorite target of quarterback Matt Hasselbeck, posting three games with 10 or more catches this season.

"I always felt like I needed to be loyal to coach Carroll. He gave me the opportunity," Williams said. "Obviously there was some excitement about free agency and the possibilities but I knew I wanted to be here and if we could get close to where I wanted to be I was going to make it happen."

Williams said the idea of an extension was first broached around midseason. Williams and his representatives wanted to delay moving forward, but the Seahawks wanted to get a deal done and not risk Williams becoming a free agent. Williams signed a one-year deal with Seattle for the 2010 season with a base salary of $545,000. Financial details of his extension were not released.

Carroll said Williams' deal is proof that there are rewards for hard work in the Seahawks system.

"It's a statement that Mike has come back for real that he is to the point where he has instilled the confidence in us to keep him around for a good while," Carroll said. "And he's still just getting started."