The fourth-year receiver reported for training camp Wednesday and promptly signed a six-year, $40.25 million deal that he earned by significantly outperforming the one he received as a fourth-round draft pick in 2010.
Some scouts rated him as a potential first-round prospect coming out of college, however many teams were reluctant to select him because of on- and off-the-field issues at Syracuse.
"I kind of put a chip on my shoulder to prove everybody wrong," Williams said. "Then when I thought about it, I said: 'Just be Mike. Show them who you really are.' This is where all the lights are, where everybody watches you. Basically who you really are now, they are going to see in the end. That's what happened. I proved to people I'm not that guy they thought I was."
Playing the side opposite of free agent acquisition Vincent Jackson, the 26-year-old had 63 catches for 996 yards and nine touchdowns to help Josh Freeman became the first 4,000-yard passer in franchise history.
Jackson, meanwhile, flourished in the first year of a contract worth over $55 million by leading the Bucs with 72 catches for 1,384 yards and eight TDs.
"We are pleased to have Mike signed to a long-term contract that ensures he will continue to be part of the exciting young core of players we are building around," general manager Mark Dominik said.
"It's a big commitment for both sides," Dominik added, calling Williams a perfect complement to Jackson. "We're very excited where this offense is, and where it's going."
Williams was entering the final season of the contract he signed as a rookie. He had 65 receptions for 964 yards and 11 TDs in his first pro season, then followed with 65 catches for 771 yards in 2011.
With 193 career receptions for 2,731 yards and 23 TDs over the past three years, Williams ranks second among receivers selected in the 2010 draft class. Dallas' Dez Bryant has 200 catches for 2,871 yards and 27 TDs.
"He's extremely productive and really bought in to who we are and what we're doing," Dominik said, adding that negotiations with Williams' agent on a deal extended over a year. "He's a big part of why we're building an explosive offense."
And, he's an example of the type of player second-year coach Greg Schiano feels is necessary to turn around the fortunes of a club that hasn't made the playoffs since 2007.
"The way he plays and practices is really important to me," Schiano said. "This is a guy who loves football."
And one who's grateful that his future didn't remain uncertain until becoming a free agent next March.
"This is everything I wanted," Williams said. "I wanted to stay here. I just can't wait to get camp started and keep doing what I'm doing."