[3][4] During the French invasion of Russia, he financed and commanded the creation of the 21st Lithuanian Infantry Regiment of the Army of the Duchy of Warsaw, which he led since 29 August 1812.

In 1818 he was appointed as a brigadier general of the 1st Brigade of the 1st Infantry Division [pl] of Kingdom of Poland army by Grand Duke Konstantin.

[5] During the November Uprising he returned to active service and initially served as a commanding officer of the 1st Brigades 1st Infantry Division under Jan Krukowiecki.

Unable to return to Polish-Lithuanian main forces at that time converging on Warsaw, he decided to head to Klaipėda, where he was expecting foreign reinforcements.

[1][2] Three to five years after the uprising, the Tsar of Russia agreed to transfer the remains of Giełgud to a cemetery in Kisiniai [lt], 10 kilometres (6.2 mi) from Klaipėda.