Authorities said the shooting happened just before 5 a.m. in the 3100 block of Spencer Highway.
According to the Hitchcock PD chief, the officer was approached by a man with a gun. That's when the officer fired his weapon and shot the man.
"Called in by off-duty officer, shot someone that was holding a gun," a 911 dispatcher was heard saying on Rangecast audio.
The injured person was taken to Bayshore Hospital in Pasadena.
SkyEye captured video at the scene which shows crime tape across a large section of the parking lot of an apartment complex in the area.