His father was Count Heinrich Diedrich Wilhelm von Keyserling, 3rd Count of Rautenburg, was a spokesman, Kreismarschall [de] and Landbotenmarschall [de] in Courland, his mother was Baroness Anna Amalie Benigna von Nolde [ru].

[9] Alexander studied at the Humboldt University of Berlin, here he met with future German Chancellor Otto von Bismarck and John Lothrop Motley, with whom he became lifelong friends.

[10] He was also a botanist and zoologist who wrote Die wirbelthiere Europa's (Vertebrates of Europe) with Johann Heinrich Blasius.

In 1853, he wrote an article which suggested that species arose from the activity of "alien molecules" acting on the embryo.

[12] In the third edition of On the Origin of Species published in 1861, Charles Darwin added a Historical Sketch that acknowledged the ideas of Keyserling.