During his period in the foreign ministry, Stresemann came more and more to accept the Republic, which he had at first rejected. By the mid-1920s, having contributed much to a (temporary) consolidation of the feeble democratic order, Stresemann was regarded as a Vernunftrepublikaner (republican by reason) - someone who accepted the Republic as the least of all evils, but was in his heart still loyal to the monarchy. The conservative opposition criticized him for his supporting the republic and fulfilling too willingly the demands of the Western powers. Along with Matthias Erzberger and others, he was attacked as a Erfüllungspolitiker ("fulfillment politician"). Indeed, some of the more conservative members of his own People's Party never really trusted him.
Stresemann was born on 10 May 1878 in the Köpenicker Straße area of southeast Berlin, the youngest of 7 children. His father worked as a beer bottler and distributor, and also ran a small bar out of the family home, as well as renting rooms for extra money. The family was lower middle class, but relatively well-off for the neighbourhood, and had sufficient funds to provide Gustav with a high-quality education.
Stresemann was an excellent student, particularly excelling in German literature and poetry. In an essay written when he left school, he noted that he would have enjoyed becoming a teacher, but he would only have been qualified to teach languages or the natural sciences, which were not his primary areas of interest. Thus, he entered the University of Berlin in 1897 to study political economy. Through this course of studies, Stresemann was exposed to the principal ideological arguments of his day, particularly the German debate about socialism.
Stresemann early developed a deep love of art and literature; his politics were liberal and passionately patriotic. He joined the National Liberal party in 1903 after a brief flirtation with Friedrich Naumann's National Socialists, and sat in the Reichstag in 1907-1912 and 1914-1918, quickly becoming Ernst Bassermann's ablest aide. Concurrently, Stresemann worked as legal counsel for a consortium of German chocolate manufacturers and in 1912 created and lobbied on behalf of a Union of Saxon Industrialists as well as other entrepreneurial enterprises. A fervent Pan-German, Stresemann before 1914 was active in both the Navy and Colonial Leagues.
The Great War was for the clever and ambitious Stresemann primarily a titanic economic struggle against Russia on land and Britain at sea. In 1917 he succeeded Bassermann as leader of the National Liberals. Stresemann quickly became a skillful and indefatigable spokesman for the military party of General Erich Ludendorff and Colonel Max Bauer, and in July helped them to overthrow Chancellor Theobald von Bethmann Hollweg because of the latter's indecisive and vacillating foreign policy; he termed the chancellor's dismissal "the most urgent imperative. . . . Nobody has confidence in him." However, Stresemann was to be disappointed when his candidate for the vacant post, Bernhard von Biilow, was passed over in favor of Georg Michaelis. While the National Liberal leader supported Ludendorff's vast annexationist program, he nevertheless differed with the general as to where that expansion lay: "Our future does not lie in the East, and the struggle for world markets we will not give up. . . . The world was our field and will be so in the future." Above all, as a true disciple of Admiral Alfred von Tirpitz, Stresemann demanded "access to the sea" and "naval bases in the wide world."
He also shared the admiral's dream of German "military, political, and economic supremacy" over Belgium, and desired to annex the French coal fields at Longwy-Briey. Stresemann adamantly opposed the Reichstag's peace resolution of July 1917, and instead wished to see the German flag wave over Calais, "a German Gibraltar on the Atlantic." Again and again, he counseled that Germany must gain "whatever we can get in the way of colonies and sea power."
Throughout 1917 the National Liberals cooperated with the Center, Social Democrats, and Progressives in a Reichstag parliamentary majority, but in January 1918, Stresemann broke with the SPD as a result of munitions strikes in Berlin. He realized in October 1918 that the war had been lost; one historian has described him as a "political tree frog," jumping whichever way the wind blew.
The revolution of 1918 was a bitter blow for Stresemann. Moreover, his application for membership in the new Democratic party was rejected, and hence in December 1918 he rallied the right wing of the former National Liberals into the German People's party. A devout monarchist, Stresemann on August 13, 1923, became chancellor in the first "grand coalition," created to master the triple crises of Franco-Belgian occupation of the Ruhr, Communist revolts in Saxony and Thuringia, and National Socialist Putsch in Bavaria. On November 23 Stresemann was forced to resign as chancellor when the SPD withdrew its support from the coalition because it felt he had overstepped his constitutional powers in suppressing Communist revolts in central Germany; Stresemann remained Germany's foreign minister until his death. The chancellorship of 100 days was a watershed both for Germany and for Stresemann: the Reich ended the costly passive resistance to foreign occupation and under Hans Luther and Hjalmar Schacht stabilized the Mark; Stresemann, who had voted against acceptance of the Versailles Treaty in 1919, gradually came round to the point of view that fulfillment represented Germany's only hope of regaining its international prestige and independence.