No one in Buffalo will soon forget.
Williams was introduced at a news conference Thursday after signing a contract touted as the richest ever given to an NFL defensive player -- a deal worth up to $100 million with $50 million guaranteed, according to his agent, Ben Dogra.
The deal was agreed to Thursday afternoon after two days of talks. Williams had been in Buffalo since the NFL's free agency period opened Tuesday, having been flown in from his home in North Carolina.
The start of Williams' news conference was delayed a little more than two hours. Without being specific, team spokesman Scott Berchtold apologized for the delay, saying there were details still being worked out.
Selected first overall in the 2006 draft by Houston, Williams had a franchise-best 53 sacks in six seasons with the Texans.
Listed at 6-foot-6 and 285 pounds, the pass rusher is a two-time Pro Bowl starter, and set a single-season team record with 14 sacks in 2007. Williams was limited to playing just five games last season as a result of a torn chest muscle. He also missed three games in 2010 after having surgery to repair a sports hernia.
After quarterback Peyton Manning, Williams has been regarded as one of the top free agents available this offseason.
The Bills regarded improving their pass rush as their top offseason priority after managing just 29 sacks last season -- 10 of them coming in one game.
Williams spent Tuesday night dining with team management and coaches at a downtown restaurant. After taking a physical and touring the Bills facility on Wednesday morning, Williams was joined by his fiancTe, who traveled to Buffalo and was provided a tour of the region.
The Williams signing comes at a hefty price for a small-market team that has hit hard times since its Jim Kelly-led heyday in the early 1990s. The Bills were 6-10 last season and have missed the playoffs for 12 straight years -- the NFL's longest active drought.
But Bills management pledged to be aggressive in free agency this offseason and now they've added a cornerstone for defensive coordinator Dave Wannstedt.
Williams joins a new-look defense that's making the switch to a four linemen-three linebackers scheme under Wannstedt, who was promoted to his post in January. Williams will fit at the right defensive end position, playing alongside tackles Kyle Williams and Marcell Dareus.
Williams is a two-time Pro Bowl player, who is expected to be fully healthy after having surgery to repair a nagging foot injury. Dareus, the third player picked in last year's draft, is coming off a promising rookie season in which he led the Bills with 5-1/2 sacks.
Chris Kelsay, a 10-year veteran, is expected to start at left defensive end.
Injuries and inexperience contributed heavily to the Bills defensive struggles. Buffalo finished 26th in the NFL in yards allowed and 30th in points allowed. Buffalo gave up 400-plus yards offense eight times last year, including a five-game run.
The 5,938 yards allowed were a franchise worst. And the 434 points allowed were the second most in team history.
Bills fans showed their support Williams throughout the talks.
At the Buffalo Sabres NHL game against Colorado on Wednesday, chants of "We want Mar-io!" were heard throughout the arena.
On Thursday morning, cars could be heard honking as they passed by Ralph Wilson Stadium. There were many fans who also showed up in the stadium parking lot looking for a chance to get a glimpse of Williams, or simply to be near their team's facility to celebrate.