Keith Johnson, 25, was arrested hours after the shootings, which also left four men injured, at the City Grill, the Buffalo News reported. More charges are likely, police said.
The victims included Daniel Mackin, 30, a Buffalo native who had returned to the city for a party to celebrate his marriage last year in Texas. Mackin's wife, also from Buffalo, was not injured, police sources said.
Police sources told the News a disc jockey turned on the lights and ordered remaining patrons to leave the restaurant when a fight broke out. Someone began shooting a short time later.
Several parties were held at the restaurant Friday night, including an informal gathering for the Mackins. A formal party in honor of their wedding anniversary was to have been held later Saturday.
"There were good people there and s--theads," a police officer said.