In September 1845 he went with his regiment to join the forces of General Taylor in Mexico; there he took part in the battles of Palo Alto, Resaca de la Palma and Monterey, and, after his transfer to General Scott's army, which he joined in March 1847, served at Vera Cruz, Cerro Gordo, Churubusco, Molino del Rey and at the storming of Chapultepec. He was breveted first lieutenant for gallantry at Molino del Rey and captain for gallantry at Chapultepec. In August 1848, after the close of the war, he married Julia T.
During the Mexican war he was twice severely wounded in a reconnaissance at Cerro Gordo, 1847, was engaged in the siege of Vera Cruz, the battles of Contreras, Churubusco, and Molino del Rey, the storming of Chapultepec, and the assault on the city of Mexico, and received three brevets for gallant and meritorious service.
In the Mexican War he won two brevets for gallantry - that of captain for Molino del Rey and that of major for Chapultepec. He served at West Point as instructor and adjutant (1849-1855), and he took part in the Utah expedition.
He served in the Mexican War under Scott, and was breveted for gallantry at Contreras and Churubusco and at Chapultepec. He became captain in 1852 and major in 1861.
The Paseo de la Reforma, the finest avenue of the city, is a broad boulevard extending from the Avenida Juarez south-west to Chapultepec, a distance of nearly three miles.