It happened around 11:20 a.m. at the branch located in the 23800 block of South Vermont Avenue near Sepulveda, according to the Los Angeles County Sheriff's Department.
Authorities say that the driver was picking up money at the branch. As he was walking back to his truck, he was approached by two men wearing masks. One of the men immediately starting shooting at the driver, hitting him in the lower half of his body, deputies said.
SkyFOX video shows bullet casings seen surrounding a Loomis armored truck.
The guard was taken to a hospital with what authorities called "non-life-threatening injuries."
According to LASD, the suspects made off with an undisclosed amount of money.
Anyone with information in the case was urged to call the sheriff's Carson Station at 310-830-1123.
City News Service contributed to this report.