Prince Paul was born 15 April, 1893 in Saint Petersburg, Russia, he was the only son of Prince Arsen(brother of King Peter I) and Princess and Countess Aurora Pavlovna Demidova (a granddaughter of the Finnish philanthropist Aurora Karamzin and her Russian husband Prince and Count Pavel Nikolaievich Demidov, and Russian Prince Peter Troubetskoy and his wife Elisabeth Esperovna, née Princess Belosselsky-Belozersky). He married Princess Olga of Greece and Denmark, a sister of Princess Marina, Duchess of Kent, in 1923. King George VI, as the then Duke of York, was best man at his wedding in Belgrade.

On 9 October 1934, Prince Paul took the Regency after his cousin King Alexander I was assassinated in Marseille, France. In his will, King Alexander named Prince Paul, as the first of three regents to govern until September 1941, when King Alexander’s son King Peter II would come of age.

In 1939, Prince Paul, as acting head of state, went to Berlin. In August 1939, the Cvetkovic-Macek Agreement set up the Banovina of Croatia. The central government retained control of foreign affairs, national defence, foreign trade, commerce, transport, public security, religion, mining, weights and measures, insurance, and education policy. Croatia was to have its own legislature inZagreb, and a separate budget.

When World War II broke out, Yugoslavia declared its neutrality. On 25 March, 1941, the Yugoslav government signed the Tripartite Pact with significant reservations as it received three notes. The first note obliged the Axis powers to respect the territorial integrity and sovereignty of Yugoslavia. In the second note the Axis promised not to ask Yugoslavia for any military assistance. In the third note they promised not to ask Yugoslavia for permission to move military forces across its territory during the war.

Two days later on 27 March, 1941, Prince Paul was forcibly removed in a coup d’état from power.

Prince Paul’s foreign policy including the signing of the Tripartite Pact was directed by the desire to give Yugoslavia as much latitude as possible in thoroughly adverse circumstances. After the fall of France and the defeat of the British, Prince Paul faced no way of saving Yugoslavia except through adopting policies of accommodation with the Axis powers. Even under those circumstances Prince Paul, outwardly neutral, remained determinedly pro-Allied. He aided Greece when Greece was invaded. He fostered military collaboration between the Yugoslav Army and the French. And for almost three years he deflected the Axis thrust toward Yugoslavia. For the remainder of the war, Prince Paul was placed, with his family, under house arrest by the British in Kenya.

Princess Elizabeth, his only daughter, obtained and published information from the Special Operations Executive (SOE) files in the Foreign Office in London and published them in Belgrade, in the 1990 edition of the Serbian-language biography of her father. The original book Paul of Yugoslavia was written by Neil Balfour, first published by Eaglet Publishing in London in 1980.

The post-war communist authorities proclaimed Prince Paul an enemy of the state; he was banned from returning to Yugoslavia and all his property was confiscated. He died in Paris on 14 September 1976, aged 83 and was buried in Switzerland. He was rehabilitated by Serbian courts in 2011, and was reburied in the family crypt in the Royal Mausoleum in Oplenac, Serbia, near Topola in central Serbia, on 6 October, 2012, together with his wife Princess Olga (1903-1997) and son Prince Nicholas (1928-1954). Prince Paul also had a son Prince Alexander (1924 – 2016) .