Like many of his ancestors, Alvensleben based his broad education on the idea that he would be involved in civil service. When the National Socialists came to power, he was forced to turn his attention to more private projects. Through his studies of palaces and gardens of the Baroque era, he became increasingly interested in his family's historical and cultural heritage. He also reconstructed the baroque park of the former Alvensleben on behalf of the owners. In 1937, he published a book about the architect of Hundisburg,
Hermann Korb, and his Brunswick castle buildings. From 1935, he initiated the restoration of the . Extensive collections of written and photographic material were created. On Alvensleben's commission and on the basis of his preliminary work, the Dutch painter Anco Wigboldus drew all of the Alvensleben family's houses in the baroque style of bird's-eye view, after having visited them in his company and ascertained their condition in past centuries under his guidance. Park and manor at Wittenmoor experienced a heyday in its development with numerous guests, lively spiritual exchange and a lot of music. In 1936, Alvensleben had to give up part of its forest areas for the construction of the military training field and in 1937 acquired the Keez estate (part of
Brüel) near Schwerin in Mecklenburg, which offered him an additional challenge both economically and in terms of design. During the Second World War, Alvensleben was a soldier in Poland, France, Russia, the Balkans, Italy and finally Norway. His diary during the war (excerpts published in 1971 under the title "Lauter Abschiede") reports on this. Together with the then Superintendent of Stendal
Hermann Alberts, he saved the valuable medieval stained glass windows of the
Stendal Cathedral by having them stored in his Wittenmoor manor house during the war. After the expropriation of his property by the so-called land reform in the
Soviet occupation zone of Germany in 1945, Alvensleben lived as a refugee in his wife's parents' house,
Haus Bodelschwingh near Dortmund. He kept himself and his family afloat with lectures on cultural history and commissioned publications. Soon agricultural and forestry tasks were once again available when his wife inherited the neighbouring small estate of . Alvensleben belonged to committees of the forestry industry, the Swedish-German Refugee Aid and the Central German Cultural Council, organised conferences, advised on questions of the restoration of historical gardens and continued his intensive research work. His publications from this period include "Die
Lütetsburger Chronik", the history of the Frisian chief family Knyphausen, and "Alvenslebensche Burgen und Landsitze" (Castles and landed estates of the Alvenslebens). He made a major contribution to the fact that the von Alvensleben family resumed their family reunions, which had begun in 1479, after the expulsion in 1945, the rescued parts of the Alvensleben fiefdom library from the 16th century were secured in their holdings and the legendary medieval family ring was given a place of safekeeping commensurate with its importance. After reunification, the ring was entrusted to the cathedral treasure in Halberstadt, the episcopal town closely associated with the family's origins. From 1914 to 1962, Alvensleben kept an extensive diary, which after his death was compiled and edited by in parts into castle books and a war diary. These are fascinating cultural-historical testimonies of strong personal expression and judgement. Alvensleben died in at the age of 65. == Publications ==