When a civil war seemed unavoidable, Ellsworth proceeded to New York City to recruit his own regiment from the city's volunteer fire companies, stating: "I want the New York Firemen, for there are no more effective men in the country, and none with whom I can do so much.
Like most Zouave regiments, the men of the 11th New York were fashioned in uniforms not typical of the standard ensemble of a Union soldier.