He later joined the Imperial Russian Army and fought in the Napoleonic Wars as a major general.

After the war, he served various diplomatic positions for Russia in the Kingdom of Naples and Holy See.

On 19 April 1823, he was appointed by Czar Alexander I of Russia to be the Russian ambassador to the United States.

[1] Tuyll was Russian ambassador at a time when Russia was asserting claims to Alaska and American Secretary of State John Quincy Adams was formulating what would come to be known as the Monroe Doctrine, portions of which were shown to Tuyll prior to their publication in an address to Congress.

His grave is unmarked and lies under a parking lot built on top of the cemetery.