From 12 January Bibikov was part of the Provisional Land Survey Department, but left on 1 February 1800. With the calling up of the militias in 1806, during the Napoleonic Wars, Bibikov was on 16 December appointed police chief of Oranienbaum district. He resumed his diplomatic career in 1808, with a posting on 10 February as extraordinary envoy and plenipotentiary minister to the Kingdom of Naples. He was recalled to St. Petersburg on 22 February 1810, and on 20 December 1810 was once more appointed to the Senate, serving in the second branch of the 5th department, and from 8 May 1811 in the first branch of the 3rd department. With Napoleon's invasion of Russia in 1812, Bibikov petitioned his uncle, Field Marshal Mikhail Kutuzov, for a post, and was given command of a detachment of the St. Petersburg militia. Bibikov now commanded a force of 5,575 people, including 4,000 militiamen, supplemented with the attachment of two squadrons of the Grodno hussars and the Polish Uhlan regiment. Bibikov and his force left St. Petersburg on 3 September, uniting with Peter Wittgenstein's army on 28 September. Wittgenstein then placed Bibikov in command of the entire St. Petersburg and Novgorod militias.