Wounded at the Battle of Fair Oaks, he returned home and later received an appointment as Captain of the 3rd Artillery and a staff officer under Gen. Henry Morris Naglee, later accompanying him to South Carolina.
During the New York Draft Riots, he along with Captain Thaddeus P. Mott and General Charles C. Dodge of the 8th Regiment Artillery, were dispatched amid reports of an estimated 5,000 rioters being assembled near Eighth Avenue and 32nd Street.
With bayonets and sabres, the regiment charged toward the rioters causing the mob to split into two groups and driven back.
However, while the rioters refused to disperse, they neither made any movement against the regiment causing the officers to hesitated in giving the order to fire.
Howell later assumed command the 3rd Battery and remained at Newbern, North Carolina until late 1863 when it moved to Norfolk and then took part in the Carratuck campaign, being stationed at Great Bridge.