Following the Revolutions of 1848, Constantine and Charles Anthony, Prince of Hohenzollern-Sigmaringen both agreed to cede their principalities to the Kingdom of Prussia and renounced their rights as sovereign princes and heads of government on 7 December 1849.

Constantine married firstly to Princess Eugénie de Beauharnais (1808–1847) on 22 May 1826 in Eichstätt.

After her death in September 1847, he married secondly (and morganatically) to Baroness Amalie Schenk von Geyern; upon their marriage, Frederick William IV of Prussia bestowed Amalie with the title Countess of Rothenburg.

The couple had three children: He also sired a daughter out of wedlock with Sophie Scherer: Constantine died on 3 September 1869 at his estate in Silesia.

Because Constantine was the final dynast male member of the Hohenzollern-Hechingen dynastic line, having no legitimate heirs from his two marriages, his title passed to the head of the House of Hohenzollern-Sigmaringen, Charles Anthony, Prince of Hohenzollern.