The 23-year-old man was working at a McDonald's location in Brooklyn when he became embroiled in a verbal argument with a female customer over food at around 7 p.m. ET, a spokesperson for the New York City Police Department said.
The confrontation escalated into a physical altercation when the woman's son, 20, got involved and the argument spilled out onto the street outside the fast food chain, police said.
The 20-year-old is alleged to have shot the McDonald's worker in the neck.
The victim was taken to the nearby Brookdale Hospital, where he remained in critical condition as of early Tuesday morning.
Police did not identify either the victim or the suspect. They said an investigation into the incident is still underway