Georg Leisner's father came from a merchant family in Eckernförde to the northwest of Kiel. His mother came from an old family of Kiel master craftsmen. Georg spent his childhood in Kiel, where he completed pre-university studies in 1891. In the same year he joined the Bavarian Army. In 1900 and 1901 he took part in the campaigns that followed the Boxer Rebellion in China and in 1904 and 1905 was involved in the "war" against the Herero people in German South West Africa, now Namibia.