Peter Karadjordjevic, the son of Prince Alexander Karadjordjevic, was born in Belgrade in 1844. He fought in the French Army in the Franco-Prussian War (1870-71).

In 1903 Dragutin Dimitrijevic, Voja Tankosic and a group of junior officers planned the assassination of the the autocratic and unpopular King Alexander of Serbia. The group stormed the royal palace and killed both the king and his wife, Queen Draga. Soon afterwards, Karadjordjevic was elected king of Serbia by the Serbian parliament and Nikola Pasic became prime minister.

During the First World War Peter accompanied his army into exile in Greece. He returned to Belgrade and was proclaimed titular king of the Serbs, Croats and Slovenes in December, 1918.

Peter Karadjordjevic died in 1921.