Rubuta ci gaba ga wannan sakin layi - May ya shafe mafi yawan aikinsa a cikin Rundunar Dragoons ta biyu, amma kuma yana da ɗan gajeren lokaci a cikin Rundunar Dragoons ta farko. A matsayinsa na Laftanar, ya shiga cikin Yaƙin Seminole na biyu
, inda ya kasance da alhakin kama wani muhimmin shugaban kabilar. A lokacin Yakin Mexico, ya umurci rundunar soja a lokacin tafiyar Zachary Taylor, kuma ya ga aikin a yakin Palo Alto, Resaca de la Palma, Monterrey, da Buena Vista. Ya bambanta kansa a cikin waɗannan ayyukan kuma a ƙarshe an ci gaba da shi zuwa matsayi na colonel, tare da matsayi na dindindin. May daga baya ya yi aiki a sassa daban-daban na iyakar Amurka, ciki har da lokacin rikicin Bleeding Kansas.