The police were called to Lejonbacken at 6:30 p.m. after reports of a man behaving aggressively with a weapon.
Police spokesperson Susanna Rinaldo declined to say what weapon the man had or what he did.
But in a message to TT, the court said the man had acted threateningly and had a knife. The court also said no member of the royal family was at the palace at the time of the incident.
The alarm prompted a large police operation. According to Aftonbladet, about 20 police cars were at the castle. Pictures and video clips show that ambulances were also called.
During the operation, the police fired live rounds at the man. He was hit and taken to hospital by ambulance.
His injuries are considered serious but not life-threatening, the police wrote on their website.
No crime classification has been made yet.
