When the American Civil War began, the students at Madison University raised a volunteer company, and offered it to United States service. In September 1861 the company became Company C, 61st New York Volunteer Infantry Regiment, and Broady became its captain. A year later Broady was promoted to lieutenant colonel, and in the spring of 1863 he became, as lieutenant colonel, commanding officer of the regiment. In the summer of 1864 Broady became, still a lieutenant colonel, a brigade commander in the Army of the Potomac. A month later he was wounded in action at the Second Battle of Ream's Station, and had to leave his command. He was subsequently mustered out of United States, outside of Petersburg, Virginia. In 1865 Broady was brevetted colonel, United States Volunteers.