The victim was identified as Courtney Taylor, of the 6800-block of South Paulina in Chicago, according to the Cook County Medical Examiner's Office.
No arrests have been made. No one else was injured in the shooting. There are currently no conventions at the hotel.
The shooting happened around 2:20 a.m. when hotel staff and guests reported that several men, who had been attending a birthday party at the hotel, began arguing as they stood near the hotel's concierge desk.
Witnesses said Taylor, who was also attending a function at the hotel, tried to break up the fight when one of the men pulled out a gun and opened fire, shooting Taylor once in the head.
"Very tough on the mother, and the mother of his child to have talked to him yesterday and have to come here to identify him at the medical examiner's office," said Andrew Holmes, a community activist.
Police found at least a half dozen shell casing and one live round at the scene.
"It's very scary because it could happen anywhere," said Ebonie Brewer, a hotel guest.
The Hyatt Regency McCormick Place released a statement Saturday morning, saying, "At Hyatt Regency McCormick Place, the safety and security of guests and associates is a top priority. This appears to be an isolated incident, however the hotel is taking all appropriate precautions in an effort to ensure that guests and hotel associates remain in a safe environment. We also want to extend our sympathies to the family of the deceased. The hotel is cooperating with the authorities on their investigation, and inquiries should be directed to the Chicago Police Department."