She was the daughter of the General of the Imperial army Baron Christoph von Benckendorff (Friedrichsham, 12 January 1749 – 10 June 1823), who served as the military governor of Livonia, and his wife, Baroness Anna Juliane Charlotte Schilling von Canstatt (Thalheim, 31 July 1744 – 11 March 1797), who held a high position at the Romanov Court as senior lady-in-waiting and best friend of Empress Maria Feodorovna.

In St. Petersburg on 1 February 1800, at age fourteen, some months after finishing her studies, Dorothea married General Count (later Prince) Christoph von Lieven.

She also became a leader of society; invitations to her house were highly sought after, and she was the first foreigner to be elected a patroness of Almack's, London's most exclusive social club, where Lieven introduced the waltz to England.

"It is a pity Countess Lieven wears skirts", the tsar wrote to his foreign minister Count Karl von Nesselrode-Ehreshoven, "she would have made an excellent diplomat."

In October 1825, when both were staying at the same resort in Brighton, Lieven in an "off-the-record" conversation with the British Foreign Secretary George Canning told him that Russia wanted bilateral Anglo-Russian mediation of the Greek War of Independence.

[12] Lieven's talks with Canning led to the Protocol of St Petersburg of 1826, in which Britain and Russia proposed to mediate, by force if necessary, the end of the Greek war.

During Prince Lieven's ambassadorship in England (1812–1834), the princess played a role in the birth of modern Greece and made a notable contribution to the creation of the kingdom of Belgium.

After more than 20 years in England, the princess was horrified at the prospect of leaving her comfortable life and all her friends there; she had no wish to return to Russia, a country where she was no longer happy and whose harsh climate she now found difficult to endure.

She never forgave her former friend Lord Palmerston, whose intransigence over what should have been a minor diplomatic row concerning the choice of the new British Ambassador to Russia, was largely responsible for the tsar's decision to recall her husband.

In 1837 she and François Guizot entered into a close personal partnership that lasted until the princess's death and included exchanging over 5000 letters;[17] he has been called the greatest, and perhaps only true, love of her life.

[20] Princess Lieven "succeeded in inspiring a confidence" with prominent men "until now unknown in the annals of England", wrote Russian foreign minister Count Nesselrode.

Parts of the Princess's diary, her correspondence with Lords Aberdeen[23] and Grey,[24][25] with François Guizot, with Prince Metternich,[26] and her letters from London to her brother Count Alexander von Benckendorff (head of the Russian secret police from 1826 to 1844) have been published.

Heyer generally portrays her as a haughty, formidable and unapproachable leader of society, but in The Grand Sophy she is described as "clever and amusing", and there is a passing reference in that book to her role as a political intriguer.