The returned jägers took part in the Finnish Civil War on the white side, and Valve fought in battles of Tampere and Viipuri as an artillery officer. In spring 1918, after the war was over, Valve started as trainer in newly founded Finnish Artillery School in Lappeenranta. In the same autumn he became commander of Heavy Artillery Battalion, from spring 1919 Heavy Artillery regiment, based in the same town. Still in 1918 Valve was promoted captain, in 1919 he became major and lieutenant colonel in 1923.