Commander of a regiment during World War I. June 1917, Head of Staff of the South-Western front. August 1917, at the Western front. Appointed Chief-of-staff of the Supreme Commander (Kerenskii), 23 September 1917.
After the October Revolution and Kerenskii’s flight, took over the duties of Supreme Commander. Refused to execute the order of the Council of People’s Commissars, 20 November 1917, to enter into peace negotiations with the Germans. Arrested, 3 December 1917, and murdered by a revolutionary mob of soldiers at Mogilev railway station.