Prince Louis-Napoléon Bonaparte, as he was known before becoming emperor, was born in Paris. He was the son of Hortense de Beauharnais, who was the daughter of Napoléon I's wife Josephine de Beauharnais by her first marriage. The identity of his biological father remains a subject of speculation, given his unhappily married mother's record of extramarital liaisons. His assumed father, however, was Hortense's husband, Louis Bonaparte, a younger brother of Napoléon I, and his whole career was built upon the (supposed) fact that he was the nephew of Napoléon I. During Napoléon I's reign, his parents had been made king and queen of a French puppet state, the Kingdom of Holland, meaning that Louis-Napoléon Bonaparte bore the title of prince. After Napoléon I's final defeat and deposition in 1815 and the restoration of the Bourbon monarchy in France, all members of the Bonaparte family were forced into exile, so the young Louis-Napoléon was brought up in Switzerland, Germany and Italy. As a young man in Italy, he and his elder brother Napoléon Louis espoused liberal politics and became involved in the Carbonari, a resistance organization fighting Austrian domination of Northern Italy. This would later have an effect on his foreign policy.

There remained in France, under both the Bourbon and then the Orleanist monarchy, a Bonapartist movement which wanted to restore a Bonaparte to the throne. According to the law of succession Napoléon I had made when he was Emperor, the claim passed first to his son, the Duke of Reichstadt, known by Bonapartists as Napoléon II, a sickly youth living under virtual imprisonment at the court of Vienna, then to his eldest brother Joseph Bonaparte, then to Louis Bonaparte and his sons. (Louis' elder brother Lucien Bonaparte and his descendants were passed over by the law of succession because Lucien had attracted Napoléon I's displeasure and had opposed Napoléon I's making himself Emperor). Since Joseph had no male children, and because Louis-Napoléon's own elder brother had died in 1831, the death of the Duke of Reichstadt in 1832 made Louis-Napoléon the Bonaparte heir in the next generation. His uncle and father, relatively old men by now, left to him the active leadership of the Bonapartist cause.

Thus he secretly returned to France in October 1836, for the first time since his childhood, to try to lead a Bonapartist coup at Strasbourg. The coup failed but he managed to escape. He tried again in August 1840, sailing a ship with some hired soldiers into Boulogne, and this time he was caught and imprisoned (in relative comfort) in the fortress of the town of Ham in the Department of Somme. While in the Ham fortress his eyesight became poor (according to 'Napoleon III and his Carnival Empire'). During his years of imprisonment he wrote essays and pamphlets that combined his monarchical claim with progressive, even mildly socialist economic proposals. In 1844 his uncle Joseph died, making him the direct heir apparent to the Bonaparte claim. He finally managed to escape to Southport, United Kingdom in May 1846 by changing clothes with a mason working at the fortress. A month later, his father Louis was dead, making Louis-Napoléon the clear Bonapartist candidate to rule France.

Louis-Napoléon lived in Great Britain until the revolution of February 1848 in France deposed King Louis Phillipe and established a Republic. He was now free to return to France, which he immediately did. He ran for, and won, a seat in the assembly elected to draft a new constitution, but did not make a great contribution and, as a mediocre public orator, failed to impress his fellow members. Some even said that having lived outside of France almost all his life, he spoke French with a slight German accent.

However, when the constitution of the French Second Republic was finally promulgated and direct elections for the presidency were held on 10 December 1848, Louis-Napoléon won in a landslide, with 5,454,000 votes (around 75% of votes) against his closest rival Louis-Eugene Cavaignac's 1,448,000 votes. His overwhelming victory was above all due to the support of the non-politicized rural masses, to whom the name of Bonaparte meant something, contrary to the names of the other contenders for the presidency which were unknown to the masses. Louis-Napoléon's platform was the restoration of order after months of political turmoil, strong government, social consolidation, and national greatness, to which he appealed with all the credit of his name, that of France's national hero Napoléon I who in popular memory was credited with bringing the nation to its pinnacle of military greatness and establishing social stability after the turmoil of the French Revolution



In the third year of his four-year mandate, President Louis-Napoléon Bonaparte asked the National Assembly for a revision of the constitution to enable the president to run for re-election, arguing that four years were not enough to implement his political and economic program fully. The Constitution of the Second Republic stated that the Presidency of the Republic was to be held for a single term of four years, with no possibility to run for re-election, a restriction written in the Constitution for fear that a President would abuse his power to transform the Republic into a dictatorship or a sort of life Presidency. The National Assembly, which was dominated by the Monarchists, opposed to Louis-Napoléon and in favour of the restoration of the Bourbon dynasty, refused to amend the Constitution.

After months of stalemate, President Louis-Napoléon Bonaparte staged a coup and seized dictatorial powers on the symbolic date of 2 December 1851, the exact 47th anniversary of Napoléon I's crowning as Emperor, and also the exact 46th anniversary of the famous Battle of Austerlitz. The coup was later declared to have been approved by the French people in a national referendum whose fairness and legality have been questioned ever since. The use of a referendum to legalise ex post facto a criminal act was an invention which Hitler and other dictators would later copy. The coup of 1851 definitely alienated Republicans from Napoléon III, and durably tarnished his reputation among later historians. Victor Hugo, who had hitherto shown support toward Louis-Napoléon Bonaparte, decided to go into exile after the coup, and became one of the harshest critics of Napoléon III.

Napoléon III paid the price for his Austrian blunder in 1870 when, spurred by the diplomacy of the Prussian chancellor Otto von Bismarck, Napoléon began the Franco-Prussian War. This war proved disastrous for France, and was instrumental in giving birth to the German Empire, which would take France's place as the major land power on the continent of Europe until the end of World War I. In battle against Prussia in July 1870 the Emperor was captured at the Battle of Sedan (2 September) and was deposed by the forces of the Third Republic in Paris two days later.

He died in exile in England, at Chislehurst (Kent), on 9 January 1873. He is buried in the Imperial Crypt at Saint Michael's Abbey, Farnborough, Hampshire, England.

Napoléon stayed at No. 6 Clarendon Square, Royal Leamington Spa between 1838-1839. The building is now called Napoleon House and has a 'Blue plaque' put up by the local council.