Raised in New Orleans, the majority of Wheat's "Tigers" were Irish immigrant dockworkers. As one observer said, they were "the lowest scum of the lower Mississippi … adventurous wharf rats, thieves, and outcasts … and bad characters generally.
Roberdeau Wheat organized the unit around three companies already forming in New Orleans: the "Walker's Guards," commanded by Captain Robert Harris; the "Tiger Rifles," led by Captain Alexander White; and the "Delta Rangers," commanded by Captain Henry Gardner. To this group, Wheat added a company he was raising -- the "Old Dominion Guards." Some of the enlisted, especially in the Walker Guards, had already served with Wheat in a filibustering expedition to Nicaragua in 1857.
Wheat wanted to outfit his command in the zouave style. A wealthy New Orleans businessman, A. Keene Richards, provided financial support to outfit the men. Richards had previously financed one of Wheat's filibusters. Organized and outfitted, the men began to drill. They were armed with Mississippi rifles and also bowie knives.
The unit quickly gained a reputation for rowdiness. One Confederate recruit from another unit wrote: "They were all Irish and were dressed in Zouave dress, and were familiarly known as Louisiana Tigers, and tigers they were too in human form. I was actually afraid of them…."