He studied philosophy and law in Paris, at the beginning of Louis XVIII's reign, in 1815. Returned in Wallachia, in 1821 he took refuge in Braşov, Transylvania (part of the Austrian Empire at the time) from the Wallachian uprising of 1821.
In 1836, he was given the administration of the Justice Department, where he set up a new commercial code, based on the Napoleonic model, and improved the criminal and civil procedures. After Grigore IV Ghica was removed from the throne, Ştirbei was a candidate for the office in the first and only elections carried under the Regulations' provisions, but renounced his votes in favour of his brother, Gheorghe Bibescu.
After the 1848 Wallachian Revolutionary Government was overthrown by Ottoman troops, and a new hospodar was to be named, Sultan ‘Abdu’l-Mijid I supported Barbu Ştirbei for the office, and he was awarded the throne for a seven-year term (under the provisions of the 1849 Convention of Balta-Liman). His reign began under the common occupation of Ottoman Empire and Imperial Russia, occupation which ended in 1851, when Barbu Ştirbei was awarded the Order of St. Anna by the Russian Emperor Nicholas I.
During his reign, Ştirbei pushed moderate reforms, such as a slight reform of the judiciary system which led to an increase in the number of solved legal disputes. He took steps to enforce a (still very conservative) land reform, by passing a law, in 1851, in which the peasants were referred to as "tenants", and which allowed them to more easily move between boyar properties. In the matter Roma slavery, Ştirbei began by limiting the internal trading in slaves, forbade the separation of families through the latter, and ultimately abolished the institution altogether.
At the beginning of the Crimean War, in 1853, Wallachia was once again occupied by Imperial Russian troops. Barbu Ştirbei stayed in Bucharest until the formal declaration of war from the Ottoman Empire, after which he fled to Vienna, only to return the following year, in the autumn of 1854, after the Russian withdrawal, when the country was under Austrian and Ottoman occupation.
In 1856, after the end of the war, at the Treaty of Paris, the question of the unification of Moldavia and Wallachia, the two Danubian Principalities, became in order. Ştirbei supported the union, although not very strongly, as he hoped to become prince of the resulting state. However, in early summer, as his term had ended, he stepped back as hospodar and left for Paris.
In 1857, he was elected deputy in the Ad-hoc divan, an assembly charged with giving Wallachia a new constitutional framework. After the divans confirmed the union of the two countries by electing Alexander John Cuza as Domnitor, he returned to Paris together with his brother Gheorghe Bibescu.
He temporarily returned to the country in 1866, in support of the newly elected Carol of the Principality of Romania. Barbu Ştirbey spent his last years in France, where he died in 1869, in Nice, after visiting Bucharest one last time in 1868.