Mamontov was born in 1869 in Saint Petersburg. After being in a school cadet in the Nicholas Military Academy, he was a student of the prestigious Nicholas Cavalry School in St. Petersburg graduating in 1890, when he joined the regiment of mounted grenadiers of the Imperial Guard as a cornet. In 1893, he joined the Dragoons Kharkov. From 1899, he commanded the Third Regiment of Cossacks of the Don. In 1904, he participated actively in the Russo-Japanese War as an officer of the First Chita Regiment, part of the TransbaikalCossack army. On 24 August 1912 he was promoted colonel. During the First World War he was from July to April 1915 commander of the Nineteenth Don Cossack Regiment, on 8 April 1915 to April 1917 Commander of the Sixth regiment of Don Cossacks, and after his promotion to major general from April 1917 to January 1918 Commander of the 6th Don Cossack Division.
After the revolution and the collapse of the front General Mamontov and his men returned to their lands of the Don, the stanitsa Nizhne-Tchirskaia. Like most of the Cossacks he was an outspoken opponent of the Bolsheviks and joined at the first opportunity to form a partisan detachment which rallied at Novocherkassk crossing the Red lines. On 12 February he joined the White Army, a loose confederation of Anti-Communist forces in the Campaign of the steppe. From July 1918 to 23 February 1919 he was commander of the eastern front of the Don Region, then the First Don Army. In July 1919 he was entrusted with the command of newly formed special troops, the Fourth Cavalry Corps of the Don. During the march on Moscow, Mamontov and his men carried out in August 1919 a raid behind enemy lines to disrupt the rear of the Red Army. His goal was to support the attack by the forces of General Anton Denikin in 1919, called 'The offensive of the armed forces of the south of Russia in 1919' in the historical literature, in the direction of Kursk and Voronezh. Mamontov’s troops consisted only of cavalry, which gave them great mobility and enabled to mount daring raid-type operations. The greatest success of the Mamontov Corps was the capture of a number of cities in central Russia, including Tambov, Yelets and finally, together with the corps of General Andrei Shkuro the city of Voronezh. The thrust of the Mamontov Corps worried the Soviet military leadership because Voronezh was only a few hundred kilometers from Moscow. After the personal order of Vladimir Lenin, they sent the bestcavalry corps of the Red Army under the leadership of Budyonny against Mamontov's Corps, who succeeded in November 1919 after a very hard and bloody fighting in the Battles of Voronezh, Kastorensk and in the Kharkov operations at the end of 1919. These two offensives were directly connected with the Orel-Kursk operation in 1919 and were part of a broad military actionin the Red Army counter-offensive in the southern front. Mamontov’s corps was routed by S. M. Budennyi’s cavalry corps at Kastornaia in November 1919. This defeat was crucial for the consolidation of the Bolshevik power and undermined the morale of the anti-Bolshevik forces. Mamontov was subsequently relieved of his command, but after a few days re-appointed to his post. Mamontov died on 14 February 1920 in Ekaterinodar of typhus.
