Wilhelm II became German emperor and king of Prussia in June 1888 after the brief reign of his father Frederick III. He sought a more personal direction of government and dismissed Chancellor Otto von Bismarck in 1890. The subsequent shift toward Weltpolitik aimed to establish Germany as a global power through diplomacy, colonial activity, and naval expansion. Admiral Alfred von Tirpitz's fleet program intensified rivalry with Britain and helped transform Europe's strategic alignments.

Wilhelm's speeches and interventions repeatedly complicated diplomacy. The Kruger telegram in 1896 angered Britain, and his statements during the deployment to China in 1900 encouraged a harsh imperial image. The Moroccan crises raised tensions with France and its supporters. The Daily Telegraph interview of 1908 caused embarrassment both abroad and within Germany, provoking criticism of his judgment and demands for tighter constraints on personal rule. His public prominence did not mean he consistently controlled the policies implemented by ministers and military leaders.

After the assassination of Archduke Franz Ferdinand in 1914, Wilhelm supported Austria-Hungary's action against Serbia through the assurance often called the blank cheque. He later considered proposals to limit escalation, but German decisions and mobilization helped produce general war. Germany's invasion of Belgium brought Britain into the conflict. During the First World War his practical authority diminished, especially after Paul von Hindenburg and Erich Ludendorff gained leadership of the military effort in 1916. The high command exerted increasing influence over economic mobilization, diplomacy, and domestic politics.

Military defeat and revolution in 1918 ended the monarchy. Wilhelm fled to the Netherlands in November and formally abdicated later that month. The Dutch government declined to surrender him for the trial proposed by the victors, and he settled at Huis Doorn in 1920. He hoped for restoration and continued expressing nationalist and antisemitic views, but never returned to power. He died in exile in 1941. His career is central to the history of German imperial ambition and the collapse of monarchical rule, but responsibility for the war cannot be reduced to one personality. Assessing his role requires separating flamboyant rhetoric and individual decisions from the institutions, alliances, and military planning that both enabled and constrained his authority.