After the October Revolution of November 1917 Bonch-Bruyevich became one of the first high-ranking army officers to rally to the new regime, with which he had a strong family link: his younger brother, Vladimir Bonch-Bruyevich was a leading Bolshevik. On 19 November 1917 he was appointed chief of staff of the Supreme Commander, Nikolai Krylenko. In March 1918 he was appointed military director of the Supreme Military Council, and chief of field staff of the Revolutionary Military Council, and played a major role at the start of the Russian Civil War in organising the Red Army and the defence of the Soviet state. Former fellow-officers now in the White army declared him an outlaw, and attempted to catch him by raiding a train which they thought he was on. This incident may have contributed to his decision to resign his command.