Investigators said Mark and Rodney Bowens were tossed out of the Get-A-Way Lounge on Wilkinson Boulevard on Sunday night because they got into an argument with employees.
They returned and opened fire, according to detectives.
An employee and customer were both shot in the legs, but their injuries are not life-threatening.
The 67-year-old owner of the bar, Roosevelt Hinton, grabbed a handgun and fired back, hitting 37-year-old Mark Bowens in the head.
Bowens is now in critical condition at Carolinas Medical Center. He is also facing a number of charges, including two counts of assault with a deadly weapon with intent to kill inflicting serious injury, possession of a firearm by a felon, assault with a deadly weapon and assault by pointing a gun.
Police said Hinton acted in self-defense and will not be charged for returning fire.
Officers aren't happy an argument escalated to this level.
"It's ridiculous. A little disagreement turned into gunfire. It's useless and unnecessary," said Charlotte-Mecklenburg police Capt. Coerte Voorhees.
Police said they haven't had problems at that bar in years.
Local resident Ronnie Payne has been to the bar and knows the owner. He said it's normally a calm atmosphere.
"It's a nice place. I've taken my wife there and never had problems," he said.
The other suspect, Rodney Bowens, ran off and police are still looking for him. He's also facing a number of charges, including assault and possession of a firearm by a felon.
Detectives are asking anyone with information about Bowens' whereabouts to call them at 704-432-TIPS.