Frederick William III was born on August 3, 1770, and became the heir apparent to the Prussian throne. He ascended to power following the death of his father, King Frederick William II, who had ruled since 1786. The coronation ceremony, held in Berlin, was a significant occasion, attended by nobles and representatives of the military and clergy, symbolizing the continuity of the Hohenzollern dynasty. The king was tasked with leading a kingdom facing various challenges such as rising nationalistic sentiments, economic fluctuations, and the overarching threat of wars linked to revolutionary movements in France.

Upon becoming king, Frederick William III was confronted with the task of reforming the Prussian state, which had lagged in adapting to the changes sweeping Europe. His early reign witnessed attempts at military, administrative, and agrarian reforms. He also faced opposition from conservative elements within the nobility and the military, making it difficult to implement sweeping changes. During his rule, Frederick William III aimed to balance between preserving the traditional monarchy and addressing the emerging demands of his subjects and the broader European context.

Moreover, Frederick William III's leadership would shape Prussian responses to subsequent conflicts, such as the Napoleonic Wars. His efforts led to the eventual rise of Prussian nationalism and fortification of military capabilities. The early years of his reign set the stage for significant transformations within Prussia that would influence the trajectory of the German states and their eventual unification later in the 19th century. Although his initial policies were met with resistance, they laid the groundwork for major reforms that would be more thoroughly realized in later administrations.