The House of Schwarzenberg originates in Franconia, where the family still owns substantial property,[citation needed] but made Bohemia their primary seat in the 17th century, also maintaining residences in Vienna. The family had possessed fiefdoms in Bohemia as far back as the Middle Ages; it was one of the richest noble families of Bohemia and Austria-Hungary, and one of the largest land owners of Bohemia.

Karel Schwarzenberg is the eldest son of Prince Karel VI of Schwarzenberg of the junior line (Second Majorat of the House of Schwarzenberg), and Princess Antonie von Fürstenberg. He is the 1,322nd Knight of the Order of the Golden Fleece of Austria.[7] He is first cousin of Princess Ira and Prince Egon von Fürstenberg and second cousin of Rainier III, Prince of Monaco. By tradition, he holds the style of Serene Highness (German: Durchlaucht).

Schwarzenberg was born in Prague and his family spoke both German and Czech. He is known today for his "slightly archaic and often earthy Czech."[3] Schwarzenberg and his parents had to leave the country after the Communist coup of 1948, and emigrated to Austria, with Swiss citizenship. He studied law and forestry at the universities of Vienna, Munich, and Graz but left studies prior to Graduation. He has two sisters, Marie Eleonore von Bredow (born 1936) and Dr. Anna Maria Freiin von Haxthausen (born 1946), and one brother, Dr. rer. oec. Friedrich Prinz zu Schwarzenberg (born 194.

On 22 April 1967, in Seefeld, Schwarzenberg married Countess Therese zu Hardegg (b. Vienna, 17 February 194. The marriage ended in divorce in 1988. The couple married for a second time on 25 July 2008. His wife spends most of her time in Vienna