Brice announced the decision on Twitter less than two weeks after deciding to leave Duke, where he started all 11 games this season.
"Thankful for this opportunity!! #Committed #RollNeers" he posted.
Brice began his career at Clemson, serving as the backup for star QB Trevor Lawrence in 2018 and 2019. He came on in relief of an injured Lawrence in October 2018, leading Clemson to a come-from-behind win over Syracuse that kept the Tigers' national title hopes alive.
Brice transferred to Duke for the 2020 season and won the starting job, but he struggled badly in the Blue Devils' offense, leading the nation with 22 turnovers. For the year, he completed 55% of his throws with 10 passing touchdowns and 15 interceptions for the 2-9 Blue Devils.
Brice earned his degree last week, walking with Clemson players at the school's graduation.
At Appalachian State, Brice figures to replace departing senior Zac Thomas, a three-year starter who finished 2020 with 22 touchdowns and 2,400 yards of offense.
The Mountaineers wrapped a 9-3 season Monday with a 56-28 win over North Texas in the Myrtle Beach Bowl.