Peterson revealed the terms via twitter Tuesday night. The Cardinals announced the deal a short time later, but did not disclose the terms.
The agreement keeps Peterson under contract with Arizona through 2020.
Peterson has made the Pro Bowl in each of his three seasons in the NFL, first as a kick returner then the last two years at cornerback, after Arizona made him the No. 5 pick overall out of LSU in 2011.
He had two years left on his original contract after Arizona had picked up its fifth-year option earlier this year.
The personable, self-proclaimed best cornerback in the NFL probably wanted the world to know his deal exceeded those of cornerbacks Joe Haden of Cleveland and Richard Sherman of Seattle.
Haden signed a five-year, $68 million contract with $45 million guaranteed and Sherman got a four-year, $56 million deal with $40 million guaranteed.
Peterson is the first to reach agreement in the initial class of the players subjected to a fifth-year option on their contract. Under the latest collective bargaining agreement, players picked 1 through 10 have a fifth-year option on their contracts that clubs can exercise.
That group includes Cam Newton and J.J. Watt.
In fact, Peterson is the first of any 2011 first-round pick to reach an agreement on an extension. A news conference with Peterson was scheduled for Wednesday morning.
''Want to thank my family, friends and teammates, all of (hash)P2Nation and the best agent in the biz,'' Peterson said in another tweet.
Peterson has jousted with Sherman over who is the best cornerback in the NFL. Peterson laid his claim to the fact he plays all over the field, defending the opponent's best receiver. Sherman plays on one side.
Both were first-team All-Pro selections last season.
Peterson and Mike Woodson are the only players to make the Pro Bowl as a kick returner and cornerback. Peterson is one of seven players to make three Pro Bowls before his 24th birthday - which he celebrated July 11.
He has started all 48 games since coming to the NFL. In those three seasons, he had 12 interceptions, 162 tackles, a sack, 60 passes defensed and a fumble recovery.
Peterson returned four punts for touchdowns as a rookie, including a 99-yarder to beat St. Louis in overtime, but has not had any since. He said he has been told he won't return punts or play on offense, as he did some last year, and will concentrate only on playing cornerback.
''I think that's just going to take my game to another level now,'' he said at his locker on Monday , ''because now I don't have to focus on the punt return, try to remember the offensive plays, or things like that. I can just hone in on playing defensive back and being the best player that I can be.''
AP NFL website: www.pro32.ap.org and www.twitter.com/AP-NFL