The 45-year-old man was in his car around 1:27 a.m. in the 5500 block of West Crystal Street when a gunman walked up and started shooting, according to Chicago police.
The concealed carry holder returned fire, striking the suspect once in the upper chest, police said.
The suspect was taken by paramedics to Loyola Hospital where he was listed in critical condition, police said. His gun was also recovered from the scene.
The concealed carry holder was not injured in the shooting. Police said the shooting stemmed from an attempted carjacking.
Area Five detectives are investigating.