Son of Pyotr Aleksandrovich Tolstoy, Yegor Tolstoy was born on 9 July 1802 (Old Style) in the Tolstoy family. He received home education and in 1819 enrolled to serve in the Uglitsk regiment. In 1821, he was transferred into the regiment of chasseurs of the Leib Guards. Tolstoy was aide-de-camp to general Alexander von Neidgart, and was stationed in Laibach (Ljubljana) during the Congress, where he was appointed head of the Russian headquarters of the detachment against Piedmont. In 1826, Count Tolstoy participated in the Russo-Persian War, 1826-1828, serving as aide de camp to Mayor-General Prince Aleksandr Sergeyevich Menshikov. On 21 April 1827 Tolstoy was appointed aide de camp to the Emperor Nicholas I of Russia. During the campaign of Russo-Turkish War, 1828-1829, he was awarded with an Order of St. George of the 4th degree and the rank of colonel for the action in the siege of Anapa. He was awarded with a golden sword for the restoration of the communication between the main army and the corps of general Loggin Rot in July of the same year; and was wounded in the head during the Siege of Varna.