"I really thought I wasn't going to do it," Krzyzewski said. "But now that I am doing it, I can tell you I am doing it with 100 percent commitment and passion but with seven years of experience of having done it before."
USA Basketball chairman Jerry Colangelo, speaking by teleconference, said the job is "a perfect fit" for Krzyzewski.
Krzyzewski took over as coach as USA Basketball began its national-team program in 2005. Since then, Krzyzewski has led the U.S. men's team to Olympic gold medals in Beijing in 2008 and London in 2012. He also led the Americans to the gold at the 2010 FIBA World Championship.
The U.S. men's national team has a 50-game winning streak dating back to 2006.
Krzyzewski's commitment to coach the team from 2013-16 means he will be on the bench for the 2014 FIBA Basketball World Cup in Spain as well as the 2016 Olympics in Rio de Janeiro.
He had said several times that London would be the final stop of his international coaching career. But Colangelo wanted to wait on any discussion until after Krzyzewski finished his season with Duke.
With Krzyzewski in charge, the Americans are 62-1 over the last seven years.
Krzyzewski has 957 career victories, most coming with the Blue Devils, and ranks as the winningest coach in Division I men's basketball history to go with four NCAA championships. Last year, Duke notched its 13th 30-win season before falling to eventual champion Louisville in the NCAA tournament's regional finals.
Current and former Duke players Seth Curry, Ryan Kelly and Andre Dawkins attended the news conference.