Rubuta ci gaba don wannan sakin layi - A matsayin ɗan na uku na wani ɗan ƙaramin reshe na gidan Fürstenberg, an shirya Karl Aloys don aikin soja. Malaminsa, Laftanan Ernst, yana aiki a cikin sojojin Habsburg, kuma ya ɗauki Karl Aloys mai shekaru shida tare da shi. Ta wannan hanyar, ya koya tun yana yaro littafin jagorar soja na Habsburg, kuma ya haɗu da manyan sojoji waɗanda daga baya suka ci gaba da iliminsa da aikinsa; ya kuma sami matsayin girmamawa a matsayin "Kreis-Obristen", ko Kanal na Da'irar Masarauta, a lokacin da yake ɗan shekara goma. Yayinda yake saurayi, a cikin 1776, ya sadu da Ministan yaƙin Habsburg Count Franz Moritz von Lacy da Baron Ernst Gideon von Laudon; an kuma gayyace shi ya ci abinci tare da Sarkin Joseph II. Ya fara hidimarsa a 1777 a matsayin "Fähnrich" (flag) a cikin ƙungiyar soja ta Habsburg. Ya ga aikinsa na farko a lokacin yakin basasa na Bavarian
(1777<unk>78), kodayake bai shiga cikin yaƙe-yaƙe ba.