Kammala jumla mai zuwa: A farkon farkon yakin duniya na Peniķis ya zama kwamandan kwamandan a Galicia da kuma fadace-fadace a kusa da Krakov. An ji masa rauni a watan Disamba na 1914. A cikin 1915 an daukaka shi zuwa matsayin colonel kuma ya shiga cikin fadace-fadace a Belorussia. A cikin kaka na 1916 an canza shi zuwa rukunin 'yan bindigar Latvia kuma ya zama kwamandan Riga na 2nd Riga Latvian Rifleman Regiment. Ya jagoranci rundunarsa a cikin
Yaƙe-yaƙe na Kirsimeti da kuma Yaƙin Jugla a cikin kaka na 1917. Bayan Juyin Juya Halin Oktoba, Peniķis ya bar rundunar kuma ya zauna a cikin Vidzeme da Jamus ta mamaye, inda aka tsare shi. An sake shi a watan Nuwamba 1918.