Marie – nicknamed "Mimi" – was born in Rome as daughter of Ludwig August von Buch, Prussian ambassador to the Holy See.

After her second husband's retirement in 1904, they resettled in Berlin, where both died shortly before the breakout of World War I. Marie von Schleinitz became a passionate fan of Richard Wagner (1813–1883) beginning from the early 1860s, when she made his acquaintance of at a concert in Breslau.

After his retirement from service in 1904, she reopened her house in Berlin, where she received personal friends and members of the political and cultural life of the Reich until her death in 1912.

Bismarck was an enemy of her husband, who had been one of the protagonists of the so-called "new era" from 1858 to 1862, when William I and his wife Augusta followed a moderate strategy of modernization and liberalization of the Prussian state.

Marie von Schleinitz stands as a symbolic figure of the liberal-aristocratic opposition against Bismarck's conservative politics during the foundation of the German Reich, as well as for a short, intense blossoming of culture and intellectuality in Germany historically located between the downfall of romanticism and the beginning of modernity.

Although Schleinitz herself was interested in music and literature much more than in politics, the alliance between the two salons, according to Petra Wilhelmy, almost amounted to an attempt of building an inner empire, binding the cultivated birth-aristocracy and the intellectual elite under liberal auspices.

[1] According to historian Michael Freund, "The greats of the country, emperors and kings, crown princes, generals, diplomats and statesmen met at Frau von Schleinitz's; But respect was also shown to leading representatives of intellectual life.