Born at Regensburg the second son of the Bavarian statesman Count Aloys von Rechberg und Rothenlöwen (1766–1849), Johann Bernhard was destined for the Bavarian public service, his elder brother being a hereditary member of the Upper House in the parliament of Württemberg.
Aloys was a prominent Bavarian statesman, while his son Johann Bernhard, would enter the Austrian diplomatic service and rise eventually to the post of Minister of Foreign Affairs.