Reddish, a 6-foot-7 small forward out of Westtown School (Penn.), chose the Blue Devils over a final five that included Kentucky, Connecticut, UCLA and Villanova.
"I'm going somewhere that I can be challenged as a leader, challenged as a student, challenged to grow up, on and off the court," Reddish said in a video on The Players' Tribune. "And that's why I'll be attending Duke University."
Reddish is one of the more versatile perimeter prospects in the 2018 class, with the ability to play point guard or on the wing. He averaged 22.6 points, 7.8 rebounds and 3.0 assists on the Nike EYBL circuit in the spring with the Team Final AAU program.
Reddish also played for Kentucky coach John Calipari on the USA U19 World Cup team over the summer, finishing second on the team in assists and averaging 10.7 points and 4.3 rebounds.
Reddish is the second top-10 prospect to join Mike Krzyzewski's program in the 2018 class, following point guard Tre Jones (No. 10), who pledged in mid-August. With No. 1 prospect Marvin Bagley III also signing last month to play in 2017-18, Duke now has reeled in six top-10 prospects in the past two classes and nine top-10 prospects in the past three classes.
The Blue Devils are also heavily involved with No. 1 senior R.J. Barrett, who will officially visit Duke later this month. Other 2018 targets on Krzyzewski's board include Darius Garland (No. 11), Zion Williamson (No. 2), Nassir Little (No. 14), Emmitt Williams (No. 20) and David McCormack (No. 33).