diplomat and foreign minister of the Habsburg Empire (1879–81) who secured a treaty with Serbia giving Austria-Hungary virtual control over Serbian foreign policy.

Entering the imperial diplomatic service in 1850, Haymerle served in Turkey, Greece (1857), and, after 1861, Germany. Following the German-Danish War (1864) between Austria-Prussia and Denmark, he was sent to Copenhagen to reestablish diplomatic relations; he held a similar position at Berlin after the Seven Weeks' War (1866) between Austria and Prussia. Subsequently envoy at Athens (1870) and The Hague (1872–76) and ambassador to Italy (1877), he assisted the imperial foreign minister, Count Gyula Andrássy, at the Congress of Berlin (1878), which was called to revise the Treaty of San Stefano, and again during the negotiation of the Austro-German alliance of 1879.

Following Andrássy's retirement, Haymerle was named foreign minister for the empire. His brief ministry saw the conclusion of the second tripartite Austrian-German-Russian treaty (Dreikaiserbund, 1881), which was of little profit to Austria-Hungary. This was followed by an overwhelmingly favourable compact with Serbia (1881), which relegated Serbia almost to the status of an Austrian satellite. Haymerle's conduct of policy owed little to personal innovation; he generally followed the diplomatic course marked out by his predecessor.