David Scannell was a firefighter, law enforcement official, and veteran of the Mexican-American War. Scannell was born in New York City in 1820, and began working as a volunteer firefighter when he was just twelve years old.In 1846 he volunteered to fight during the Mexican-American War, and was commissioned as a Lieutenant in the 2nd Regiment of Foot of New York. His unit fought at the battles of Veracruz, Cerro Gordo, Contreras, Churubusco, Chapultepec and Garita de Belen. His unit experienced extremely heavy casualties, but Scannell returned to New York uninjured.