Duval made his announcement on The Players' Tribune website.
"I'm excited to evolve as a student, as a basketball player and now, and forever, as a Blue Devil," Duval said in his announcement video.
Duval, a 6-foot-3 point guard from Delaware who played this past season at IMG Academy (Florida), is the No. 1 guard and No. 5 overall prospect in the 2017 class. He chose the Blue Devils over Kansas, Seton Hall, Baylor and Arizona.
Duval took visits to all five schools, but Duke made the strongest push over the past couple of months. Frank Jackson's decision last week to keep his name in the NBA draft heightened the need for Duke coach Mike Krzyzewski to close Duval, as the only other point guard on the roster was incoming freshman Jordan Goldwire, a three-star prospect.
Duke lost Jackson, Luke Kennard, Jayson Tatum and Harry Giles early to the NBA draft after last season, while Amile Jefferson and Matt Jones were seniors, and Sean Obi and Chase Jeter both transferred.
Duval joins a top-five recruiting class that also includes the top-ranked shooting guard and power forward in the 2017 class. Wendell Carter (No. 4) and Gary Trent Jr. (No. 7) headline the rest of the group, along with ESPN 100 prospects Jordan Tucker (No. 40) and Alex O'Connell (No. 84), and Goldwire.
Duval averaged 16.1 points and 7.5 assists as a senior at IMG this past season and was chosen as a McDonald's All American.
Duke has now landed 11 top-five prospects in the ESPN 100 era -- one more than Kentucky, according to ESPN Stats & Information.