Kammala wannan magana: Haller ya yi yaƙi da Seminole Indians a Florida a 1840-1841 kuma daga baya ya yi aiki tare da bambanci a Monterrey,
Veracruz, da sauran fadace-fadace a lokacin Yakin Mexico da Amurka, suna aiki a cikin wannan rundunar kamar Ulysses S. Grant. Ya bambanta kansa a cikin Yaƙin Churubusco, inda ya taka muhimmiyar rawa a harin da aka kai a Molino del Rey. A shekara ta 1852, sojojin sun ci gaba da Haller zuwa manyan kuma suka tura shi a 1853 zuwa yankin Washington, wanda aka kafa a Fort Dalles, Oregon tare da raka'a na 4 na Amurka. Ya shiga cikin yaƙe-yaƙe na Arewa maso Yammacin Indiya na 1855-56 da rikicin iyakar Yakin Pig na San Juan Islands tsakanin Amurka da Burtaniya a 1859.