The new agreement will bring coverage of more than 60 live games a season to satellite TV viewers in the UK across 2012, 2013 and 2014, including the International Series games at Wembley Stadium in October, the playoffs and the Super Bowl.
Alongside television, the multiplatform deal also includes rights to coverage across mobile, online and tablet devices. Financial terms were not disclosed.
The new season will get under way on Sky with the opening game on Wednesday (September 5) between the Dallas Cowboys and Super Bowl champions, the New York Giants.
In all the next three seasons, Sky will broadcast two live primetime fixtures every Sunday at 6pm and 9.15pm on one of Sky Sports 1, Sky Sports 2 or Sky Sports 3, in both standard and high definition.
The broadcaster will also show three Thanksgiving Day clashes and regular matches on Thursday nights.
For the Playoffs and Super Bowl each season, there will be live coverage of every wild card, divisional and Conference Championship playoff match, plus the annual season ending Super Bowl.
Initial NFL games due to be shown on Sky Sports in 2012 include:
Dallas Cowboys at New York Giants, September 5 at midnight on Sky Sports 1
Indianapolis Colts at Chicago Bears, September 9 at 5.30pm on Sky Sports 2
San Francisco 49ers at Green Bay Packers, September 9 at 9.15pm on Sky Sports 2
Chicago Bears at Green Bay Packers, September 13 at 1am on Sky Sports 1
New Orleans Saints at Carolina Panthers, September 16 at 5.30pm on Sky Sports 3
Washington Redskins at St Louis Rams, September 16 at 9.15pm on Sky Sports 3
The NFL RedZone score update show will be available every Sunday of the regular season via the Sky red button, and NFL Total Access will air twice a week.
"This new deal is great news for NFL fans in the UK - primetime coverage of two matches on Sunday evenings, RedZone, the International Series and Super Bowl all for the next three years," said Cardle.
"We start our new season with some great games - last season's Super Bowl champions New York Giants at home to the Dallas Cowboys, then the Indianapolis Colts who include No1 draft pick Andrew Luck away to the Chicago Bears, and on the following Thursday we get our first look at the St Louis Rams, who will be coming over to the UK for the International Series in October.
"There are so many ways for NFL fans in the UK to keep up with what's going on, including RedZone during our live match coverage, and fans can let us know what they think about the game using our Twitter page @SkySportsNFL."
Alistair Kirkwood, the managing director of NFL UK, said that he is "delighted" to extend the relationship with Sky into its 20th year.
He added: "Through their coverage the game has attracted many new fans in this country, and we look forward to another three seasons of excellent coverage, including the International Series matches at Wembley and the next three Super Bowls."