In 1785, when Augustus was two years old, his father became Prince-Bishop of Lübeck and was furthermore appointed regent of the Duchy of Oldenburg for his incapacitated cousin William, Duke of Oldenburg. From 1788 to 1803, the two princes were educated at home under the supervision of their father. Together with his brother, he studied at the University of Leipzig from 1803 to 1805. From 1805 to 1807 he and his brother travelled extensively in England and Scotland. In 1808, he accompanied his father to the Congress of Erfurt, the meeting between EmperorNapoléon I of France and Tsar Alexander I of Russia. Between 1810 and 1814, Oldenburg was occupied by Napoleonic France. In December 1810, the Duchy of Oldenburg was annexed by the French Empire and Augustus and his father traveled to Russia to stay in exile with their relatives, the Russian imperial family. This annexation was one of the causes for the diplomatic rift between former allies France and Russia, a dispute that would lead to war in 1812 and eventually to Napoleon's downfall. From 1811 to 1816 he was Governor of Estonia where he led the work to prepare the abolition of serfdom. He participated in the Napoleonic Wars from 1812 to 1814. After the end of the Napoleonic Wars, he returned to Russia to finish his work as governor of Estonia. He returned to Oldenburg in 1816.
In 1823, his father succeeded as Duke of Oldenburgafter the death of his cousin William, Duke of Oldenburg and Augustus became Heir apparent. Although Oldenburg, like many other German duchies, had been elevated from a mere duchy to a grand duchy in 1815 at the Congress of Vienna, his father chose to continue the use of the lesser title of Duke, making Augustus the Hereditary Prince rather than the Hereditary Grand Duke of Oldenburg. As Hereditary Prince, he participated extensively in the government of the duchy.
Second marriage
On 24 June 1825, after five years as a widower, Augustus married secondly Princess Ida of Anhalt-Bernburg-Schaumburg-Hoym, a younger sister of his first wife. Augustus and Ida had one son, Peter, who was born in 1827 and would later succeed Augustus as Grand Duke. Just like her sister, however, Princess Ida died after three years of marriage, in 1828.
Reign
Augustus succeeded his father, Grand Duke Peter I, to the throne of Oldenburg, and the :de:Fürstentum Birkenfeld|Principality of Birkenfeld on 21 May 1829. Unlike his father, Augustus assumed the title of Grand Duke, and Augustus was thus the first to use the title Grand Duke of Oldenburg. As Grand Duke, Augustus was employed in reforming the administration of his small state and showed himself a patriarchal ruler who cared for agriculture, transport, social welfare, art and science. Trade flourished along the lower Weser and Jade, and the city of Oldenburg developed into one of Northwestern Germany's cultural centres. The Grand Duke however was reluctant to follow popular demands to introduce a constitution for the Grand Duchy. Although article 13 of the constitution of the German Confederation obliged Oldenburg to have a constitution, following the advice of his Russian relatives, the Grand Duke again and again postponed the promise of a constitution given in 1830. Only as a consequence of the Revolutions of 1848 did the Grand Duke reluctantly give in under pressure from his advisers. On 18 February 1849, he signed the Oldenburg constitution which had already been revised by 1852.
Grand Duke Augustus died on 27 February 1853 in Oldenburg. He was buried in the Ducal Mausoleum in the Churchyard of Saint Gertrude in Oldenburg. Augustus was succeeded as Grand Duke by his eldest son, Peter.