After being drafted in the second round of the 2004 NFL Draft by the Cincinnati Bengals, Williams contributed early by playing in all 16 games. He finished the season with 103 tackles, 11 pass deflections, two sacks, and three interceptions. He returned one of the interceptions for a touchdown. In 2005, Williams only played in 4 games, missing the other 12 due to injury. He did, however, record 23 tackles and an interception. In 2006, Williams returned to play all 16 games of the season. He finished the season with 90 tackles, 13 pass break-ups, two forced fumbles, and three interceptions. In 2007, injuries again caused Williams to miss three games of the season. He finished up the season with 74 tackles, 7 pass deflections, two sacks, one forced fumble, two fumble recoveries, and two interceptions. He opened up the season with 10 tackles in the Monday Night Football opener against the Baltimore Ravens.
Minnesota Vikings
After spending his first four years with Cincinnati, Williams signed with Minnesota following the 2007 season. He agreed to a six-year, $33 million contract. He missed the first 7 games of the 2008 season due to a neck injury he suffered during training camp. In his first game back he intercepted Sage Rosenfels to wrap up the win for the Vikings. He finished the 2008 season with 42 tackles and 2 interceptions. On July 28, 2011, he was released.
Williams signed with the San Francisco 49ers on August 1, 2011.
Washington Redskins
Williams signed with the Washington Redskins on April 10, 2012. He became the Redskins' starting free safety after Tanard Jackson, his main competition for the starting position, was suspended for an entire season. In Week 6 win against his former team, the Minnesota Vikings, he intercepted a pass from Christian Ponder and returned it 24 yards for a touchdown.
Training methods
Madieu trains with an athletic group known as "The Stable", to whom he has credited to his success stemming from his freshman year in high school. "This is home, and I feel good when I’m working out," said Williams, who’s headed into his fourth season. "It’s a lot of guys that put in a lot of work getting ready for whatever sport that they play. It’s a lot of camaraderie beyond us training."
Community service
The Madieu Williams Foundation, founded in 2005, focuses on health, wellness, nutrition, fitness and education. Through his foundation, Madieu reaches out to youth and teaches them at an early age the importance of a healthy lifestyle. Recently, Madieu Williams was honored by Hall of Famer Franco Harris and Harris' company, R Super Foods, as their Cincinnati Super MVP. In 2009, Williams donated $2 million to the University of Maryland to help create the Madieu Williams Center for Global Health Initiatives. It is the largest gift to the university by an African-American alum. On February 6, 2011, Williams received the Walter Payton Man of the Year Award. Every year, on Maryland Day, Williams hosts a free football camp run by former and current terps college and NFL players. Players like Torrey Smith have attended the camp and have coached ages 6–14.
