It happened around 2:30 a.m. on Hazelwood Boulevard and Orleans Avenue, south of Butler Avenue.
Police say the shooter knocked on the victim's door. When the 51-year-old resident answered, the suspect asked if a certain person was inside the home.
The victim said he had never heard of that person, and as he went to shut the door, the suspect opened fire.
A shot was fired through a metal screen door, grazing the victim in the forehead.
Officials say he is expected to be OK.
Police have not yet released a description of the suspect.