Police were called to the Gateway Inn at 8911 Atlantic Ave. near Firestone Boulevard about 3 a.m. when the officer-involved shooting occurred.
The man was identified as Martin Tadeo Osuna-Aguilar, 23, of Lynwood.
The motel's receptionist said in a telephone interview that he heard more than one shot fired as he was sitting behind his desk at the 50-room motel.
Details of the circumstances surrounding the shooting were not immediately available.
The Los Angeles County Sheriff's Department said it was helping South Gate police investigate the shooting.
City News Service contributed to this report.