I te tau 1841, ka riro a Scott hei Kaihautū Nui o te Ope Taua o te Hononga o Amerika, i te whiunga i tana hoa whawhai a Edmund P. Gaines mo te tūranga. Whai muri i te pakarutanga o te Pakanga Mexican-American i te tau 1846, i tukuna a Scott ki tetahi mahi whakahaere, engari i te tau 1847 i arahi ia i tetahi pakanga ki te taone nui o Mexico o Mexico City. I muri i te hopu
I te taone nui o Veracruz, i hinga ia i nga ope a te rangatira Mexico a Antonio López de Santa Anna i nga pakanga o Cerro Gordo, Contreras, me Churubusco. I riro ia i te taone nui o Mexico, i muri i tana pupuri i te tikanga i te taone nui o Mexico me te awhina a-kore ki te karere a Nicholas Trist ki te whakawhitiwhiti korero mo te Tiriti o Guadalupe Hidalgo, i mutu ai te pakanga.