In 1864, the corps of the Kuban Cossack army was released from the Aleksanrovsky School of the Coroon into the equestrian artillery No.
At the end of 1876, Domontovich was sent to the disposal of the chief of the Erivan detachment, Lieutenant General Tergukasov, with whom he took part in the occupation of Bayazet, Diadin, Surp-Oganez and Big Karakilisa, in the battles on the Drum-Dagh Heights and at Dayar and in the movement of Erivan squad to the rescue of the Bayazet garrison surrounded by the enemy, as well as in the battles of Igdir and Deva Boynu.
Appointed at the end of the war as the chief officer for special assignments at the headquarters of the Caucasian military district, Domontovich was sent to Persia in November 1878, where, at the request of the Persian government, he examined the local troops and made proposals for improving the armed forces of Persia.
In 1885, Domontovich was appointed chief of staff of the Caucasus Cavalry Division (Russian Empire), and in 1886 - commander of the 1st Gorsko-Mozdok equestrian regiment of the Tersky Cossack army.
In 1899 he was enlisted in the lists of the General Staff and received the command of the 2nd Combined Cossack Division (Russian Empire).