Kammala jumla mai zuwa: A cikin 1918, bayan "Charge a Rarańcza", a matsayin kwamandan rundunar Sojojin Poland ta 2 tare da Sojojin Austriya, Haller ya keta layin gaba na Austro-Rasha zuwa Ukraine, inda ya haɗu da sojojinsa tare da rukunin Poland waɗanda suka bar sojojin Tsarist. Ya nuna rashin amincewa da Yarjejeniyar Brest-Litovsk kuma ya ci gaba da yaƙi da Rasha tare da Brigade na II na Legions na Poland (daga baya, 4th da 5th Rifle Divisions na Polish II Corps). A karkashin matsin lamba na Jamusawa, waɗanda bayan Zaman Lafiya na Brest-Litovsk suka ɗauki kasancewar sojojin Poland a cikin Ukraine ba bisa ƙa'ida ba, kuma suka nuna mummunan hali
Yaƙin tsakanin 'yan Poland da Jamusawa a Kaniów (10 ga Mayu, 1918, raunin 2500) an tsare rukunin sa, yayin da Brigadier da kansa ya sami damar tserewa zuwa Moscow. Daga baya, ta hanyar Murmansk, ya isa Faransa a watan Yulin 1918, inda a madadin Kwamitin Kasa na Poland ya kirkiro abin da aka sani da Blue Army (daga launi na rigunan Faransanci, wanda aka fi sani da "Haller's Army"). A cikin 'yan watanni masu zuwa sojojinsa, da suka hada kai da Entente, za su yi yaƙi da Jamus. A shekara ta 1919, a matsayin sabon shugaban sojojin, ya isa Poland kuma aka tura shi zuwa gaban Ukraine. A cikin 1920 Haller ya kwace Pomerania kuma ya shiga Danzig (Gdańsk) da sunan Poland, kuma a lokacin Yakin Poland da Soviet ya jagoranci rundunar masu sa kai. Ya kuma kasance Sufeto Janar na Sojoji kuma memba na Majalisar Yaƙi.