Hasan is accused of killing 13 and wounding more than 30 others during a shooting rampage at Fort Hood, Texas.
The Army psychiatrist has grown a beard while in prison awaiting trial and his defense attorneys appealed a trial judge ruling that ordered the beard removed -- including forcible removal if necessary -- to comply with Army standards. Hasan's legal team argued that Hasan's beard was integral to his Islamic religious beliefs.
However, the U.S. Army Court of Criminal Appeals issued the clean-shaven ruling Thursday, upholding the trial judge's decision.
According to a Fort Hood news release, two members of the appeals court partially dissented with the ruling saying that "the judge's order to require Hasan to appear in court clean shaven compromised his impartiality." However, the court majority "did not question the judge's impartiality," according to the Fort Hood account.
The appeals court also upheld previous contempt rulings against Hasan totaling $1,000 in fines for appearing in court on six occasions out of uniform because of his beard.
Hasan's defense counsel said they will appeal the decision to the U.S. Court of Appeals for the Armed Forces.