 Alvensleben was born on May 19, 1902, in Wittenmoor (now part of Stendal) to Ludolf Udo von Alvensleben (1852–1923) and Ida, née von Glasenapp (1866–1924).He was taught in various convent schools at Magdeburg in Brandenburg an der Havel and passed his Abitur in 1921 at the Klosterschule Roßleben.After four years of practical training he commenced studies in agriculture, forestry, and law in Eberswalde and Munich.