Born into the Silesian (Protestant) branch of the ancient Haugwitz family, he studied law before being elected in 1791 by the Silesian estates as general director of the province. Frederick William II appointed him to the Prussian civil service and he became ambassador at Vienna in 1792, also becoming a member of the cabinet at Berlin in the same year as Foreign Minister.
Although the Prussian government was opposed to the attitude of the French émigrés and to any interference in the internal affairs of France during the French Revolution, nevertheless in the face of the Comité de Salut Public Haugwitz entered on the negotiations that resulted in a subsidy treaty between Great Britain and Prussia, and Great Britain and Holland, signed at the Hague on April 19, 1794. Prussia however failed to make any effective use of the money supplied, and Pitt was alienated by the Prussian actions. As a result in the October of the same year, Britain repudiated the Hague treaty and Prussia signed a separate treaty with France at Basle on 5 April, 1795, mainly due Haugwitz's influence.
During the rise of Napoleon, Haugwitz first tried to save the provinces on the left bank of the Rhine from being lost to the Holy Roman Empire. No guarantee of their maintenance had been inserted in the Basel treaty; but Haugwitz and the king hoped to preserve them by establishing the armed neutrality of northern Germany and securing its recognition by the French Republic. This policy was rendered futile by the victories of Napoleon Bonaparte during the First Italian campaign and the later conquest of southern Germany by the French. Haugwitz recognized this fact and urged his master to join the Second Coalition in 1798. However, with the king committed to an impossible neutrality, Haugwitz found himself pursuing policies of which he did not approve. However, he did not take the final step of resignation until 1803, when the king refused his urgent advice to demand the evacuation of Hanover by the French. In August 1804 he was replaced by Hardenberg and retired to his estates.
Haugwitz was much consulted in his retirement and used all his influence to counter Hardenberg's policy of rapprochement with France. This had little effect until the violation Prussian territory as French troops heading for Austerlitz marched through Ansbach, rousing the king's anger. Haugwitz was recalled as foreign minister, as Hardenberg's colleague, and sent off to Austerlitz to Napoleon with the Prussian ultimatum, produced when the Tsar visited the Prussian king in Berlin in the November of 1805. A mixture of his own temporising and Napoleon's suspicions of Prussian opposition led to the delay of the crucial meeting with Napoleon. Tallyerand kept Haugwitz kicking his heals at Vienna while Napoleon completed the job at Austerlitz. On their meeting on 15th of December, Haugwitz had no other choice to cede to the arbiter of Europe and sign the Schönbrunn treaty rather than delivering his ultimatum. The treaty was a swap: Hanover (technically the British king's personal possession but occupied by French troops) to Prussia in return for Ansbach, Cleves and Neuchâtel.
In February 1806 Haugwitz went to Paris to ratify the treaty of Schönbrunn and to attempt to secure some modifications in favour of Prussia. He was received with a storm of abuse by Napoleon, who insisted on tearing up the treaty and drawing up a fresh one, which doubled the amount of territory to be ceded by Prussia and forced her to a breach with Great Britain by binding her to close the Hanoverian ports to British commerce. The treaty, signed on February 15, left Prussia wholly isolated in Europe.
Haugwitz was to remain head of the Prussian ministry of foreign affairs, but he was unable to control the course of Prussian policy. The Prussian ultimatum to Napoleon was forced upon him by overwhelming circumstances, and with the Battle of Jena, on October 14, his political career came to an end. He accompanied the flight of the Prussian king into East Prussia, and then took leave of him and retired to his Silesian estates. In 1821 he was appointed Curator of the University of Breslau; in 1820, owing to failing health, he went to live in Italy, where he remained till his death at Venice in 1832.