The manager of the International House of Pancakes was escorting the combatants out of the restaurant and was killed when the shooting started, one witness told CBS New York.
The slain manager was identified as Papa Khaly Ndiaye, 30. He died shortly after arrival at a Newark hospital.
Two other men were wounded. One remained hospitalized Sunday in stable condition.
WABC-TV in New York said the search for the gunman continued into Saturday night.