When he was 16, Posipal's family relocated to Germany. In his youth his sportive activities focused on swimming and track-and-field as well as handball. In 1949 he joined Hamburger SV as then coach Georg Knöpfle was looking for a forward.
Posipal's family relocated to Germany when he was sixteen years old. He enjoyed participating in swimming, track and field, and handball during his youth. In 1949, he joined Hamburger SV, a team coached by Georg Knöpfle.