Baron Johann von Wessenberg-Ampringen was an Austrian diplomat statesman.
Wessenberg was born in Dresden, where his father worked as a tutor to the princes of the electoral House of Wettin. Johann's younger brother Ignaz Heinrich von Wessenberg later chose an ecclesiastical career and in 1801 was appointed Vicar general of the Bishopric of Constance. In 1776 the family returned to Freiburg in Further Austria.
Johann joined the Austrian civil service in 1794. He served as a diplomatic envoy during the War of the Second Coalition supporting the forces of Archduke Charles. From 1801 he worked as a secretary at the Austrian embassy in Berlin led by Count Johann Philipp von Stadion and in 1805 was appointed ambassador at Kassel, where he witnessed the occupation by the French troops under General Mortier in 1806.
In 1808 Wessenberg returned to Berlin as ambassador at the Prussian court. King Frederick William III had fled from Napoleon's forces to East Prussia and Wessenberg had no opportunity to convince him to join the Fifth Coalition against France. From 1811 to 1813 on he led the legation at Munich and afterwards travelled as special envoy to London, France and Milan before in 1814 he was appointed second Austrian delegate at the Congress of Vienna. Wessenberg efforts made a major contribution to the establishment of the German Confederation. From 1830 he again served as ambassador at Den Haag, he also took part in the proceedings after the Belgian Revolution that finally led to the 1839 Treaty of London.