De Alencar, 37, died of injuries from enemy small arms fire while his unit was conducting counter-ISIS operations in Nangarhar Province, according to the release.
De Alencar's remains are scheduled to arrive at Dover Air Force Base, Delaware, on Monday evening, according to a release from Air Force Mortuary Affairs Operations.
The weapons sergeant was assigned to 1st Battalion, 7th Special Forces Group, based at Eglin Air Force Base, Florida.
The Edgewood, Maryland native, whose father is an Army veteran, enlisted in 2009 and graduated from the Special Forces Qualification Course in 2016, according to his bio.
His awards include the Purple Heart, five Army Commendation Medals, six Army Achievement Medals, the Iraq Campaign Medal with two stars, the Combat Infantryman Badge, the Expert Infantryman Badge, the Special Forces tab, the Ranger tab, the Parachutist Badge and the Air Assault Badge.