Rubuta ci gaba don wannan sakin layi - A farkon matakan Yaƙin Duniya na Peniķis ya yi aiki a matsayin kwamandan kamfani a Galicia da kuma yaƙe-yaƙe 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 yakin Kirsimeti.
da kuma a yakin 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.