J.L. Brent was a recently matriculated lawyer and resident of Louisiana prior to moving to California in order to establish a practise. He decided to throw his lot in with the Confederacy and contacted his friend and fellow Californian General Magruder. Magruder placed Brent on his staff as a volunteer aide until being assigned to ordnance duty.

In Brent's words:

"I was assigned to ordnance duty, of which I was entirely ignorant, but fortunately I found in Richmond a manual of Ordnance of the United States, which I bought and studied and which proved invaluable to me, especially after I became Chief of Ordnance in Louisiana."