A prominent courtier during the reign of King Gustav III of Sweden, he was also a politician, diplomat and member of the Swedish Academy, holding seat number 8.

Amongst other things, Oxenstierna is also known for his translation into Swedish of John Milton's epic blank verse poem Paradise Lost.

Johan Gabriel Oxenstierna was born at the Skenäs estate, by lake Kolsnaren (now in Vingåker Municipality), in the province of Södermanland.

[1][2][3] The grandparents took active part in the upbringing of young Johan Gabriel - the grandfather until he died in 1752 - as the parents at times resided at Carlsten, due to the fathers military career.

The diary, which was written in French, reveals a melancholic and emotional character and a deep interest in nature and poetry, rather than the rational philosophy of that time.

He seems to have been rather uninterested in his diplomatic work in Vienna, and more interested in his poetry and in a letter exchange with an Austrian lady, which showed clear Rousseauan influence.

[2][4] He was made a senior Chamberlain in 1783 and a Member of the College of the Chancellery in 1785, with a special assignment to work with matters relating to Pomerania and Wismar.

[8] When the Privy Council was dissolved and the office of College of the Chancellery abolished in 1789, he was made Head Steward for the queen, and in the absence of the king during the Russo-Swedish War (1788–1790), he was a member of the Cabinet.

[4] Oxenstierna often got distracted from his work, his mind wandering to more interesting matters, to the extent that he sometimes wrote public documents in verse.