Kammala jumla mai zuwa: McClernand ya yi yaƙi a cikin Yakin Spain-Amurka, yana aiki a cikin yakin Santiago. Daga baya ya ga sabis a cikin
Tashin hankali na Philippine, yana jagorantar rundunar sojan doki ta 1. An ci gaba da shi zuwa Brigadier Janar ba da daɗewa ba kafin ya yi ritaya daga aiki a ranar 29 ga Disamba, 1912. An kira shi zuwa aiki na aiki a rana mai zuwa, yana aiki a matsayin Shugaban Hukumar Cavalry har zuwa 1914. Ya zauna a Easton, Pennsylvania, inda ya rubuta "Tare da Indiyawa da Buffalo a Montana", don Jaridar Cavalry a 1925. Ya mutu a ranar 9 ga Fabrairu, 1926 kuma an binne shi a Sashe na 3, Lot 1931-SW na Arlington National Cemetery.