Browner told ESPN's Josina Anderson of the agreement before confirming it on Twitter:
Today, I am proud to announce that I am a New England Patriot. I am honored that the Patriots are (cont) http://t.co/mJmk9yN7Jo- Brandon Browner (@bbrowner27) March 14, 2014
The deal is for three years and carries a maximum value of $17 million, Browner told Anderson. The Patriots announced the signing in a release Saturday.
Browner, a 2011 Pro Bowler, is suspended for the first four games of the 2014 regular season after violating the league's substance-abuse policy. His suspension also included the last two games of the 2013 regular season and last season's playoffs. He will be allowed to attend training camp and play in exhibition games.
Browner also was suspended four games in 2012 for violating the NFL's policy on performance-enhancing drugs.
He's the second high-profile cornerback added to the fold for the Patriots, as the team agreed to terms on a two-year deal with Darrelle Revis on Wednesday night.
Browner, 29, played and started eight games for the Seahawks last season, recording 19 tackles and one interception.
Revis and Browner headline a cornerback group that no longer includes Aqib Talib, who recently agreed to a deal with the Denver Broncos. The rest of the position group is highlighted by Alfonzo Dennard, Logan Ryan and Kyle Arrington.
Browner is regarded as one of the most physical cornerbacks in the NFL with his 6-foot-4, 220-pound frame.
The Associated Press contributed to this report.