He was born Gabriel-Charles-Louis-Bonnaventure, Count de Ficquelmont at the Castle of Dieuze, in his family's estate in the present-day French département of Moselle.

A member of a noble family from Lorraine dating back to the 14th century (House of Ficquelmont), he was introduced to King Louis XVI at Versailles in 1789.

His mission was to smooth relations between Austria and the newly elected heir to the Swedish throne and former French General Bernadotte in order to maintain him within the coalition during the progressing towards the Congress of Vienna.

The Holy Alliance feared the revolt might spread to other Italian states and turn into a general European conflagration, so Austria sent an army to march into Naples to restore order.

He soon gained enormous influence over king Ferdinand I and Neapolitan elites and practically administrated the kingdom, ensuring Austria's grasp over its domestic and foreign policies.

The Saltykov Mansion that was the Austrian Embassy had been described as a "place of wisdom and intelligence"[3] and as "(...) the setting the two most illustrious salon of the period (1830s), reigned over by Ficquelmont's wife".

[4] Ficquelmont's and Dorothea's influence in Russia was long-lasting and as a sign of his appreciation, Emperor Nicolas I awarded him the Orders of St. Andrew, St. Alexander Nevsky, St. Vladimir, and St. Anna.

From 17 March until the fall of the Kolowrat cabinet on 3 April, Ficquelmont took charge of the Department of Foreign Affairs and the War Ministry.

It was a violent period, his wife Countess Dolly, who was at their Venice's palace at the time,[7] was arrested twice by the Venetian guarda civil and finally had to flee the city on board an English ship with her daughter, son-in-law, and grandchildren.

Moreover, Ficquelmont's kinsman in the War Ministry, count Theodor Franz Baillet von Latour, was lynched during the Vienna Uprising of October 1848.

In 1852, Emperor Franz Joseph I of Austria made Ficquelmont a Knight of the Golden Fleece, the most prestigious order of the Empire.

Countess Dolly was also famous for her letter-writing and diary (the former was published in Italian and Russian in 1950) telling of her life as a high society's aristocrat in 19th-century Europe.