Battle of Churubusco
Casey was born in East Greenwich, Rhode Island. He graduated from the United States Military Academy in 1826 (39th out of 41). He fought in the Second Seminole War under William J. Worth from 1837 to 1842. During the Mexican–American War he fought at the Battle of Contreras and Battle of Churubusco, and was appointed brevet major on August 20, 1847 for gallant conduct. He then fought in the Battle of Molino del Rey and was severely wounded during the Battle of Chapultepec on September 13, 1847.