Born July 26, 1897, in Wattens in the Austrian Tyrol, Jakob was the seventh son of Martin Gapp and Antonia Wach. He attended elementary school in his native village and pursued his high school studies in Hall. On May 24, 1915, Italy declared war on the Austro-Hungarian Empire. This same year, Jakob enlisted in the Austrian army. He was sent to the Italian front, where he was wounded and decorated for his courage. At the end of the war he was taken prisoner. He underwent a great deal of suffering during his captivity. During the war Jakob came under the spell of an idealistic socialism, which led to a crisis of faith. On August 13, 1920, Jakob entered the Marianist novitiate at Greisinghof (Austria).