He graduated with a first-class diploma, and during his studies, he was promoted to lieutenant (XII rank) on 15 April 1859.

During the fighting, on June 12, Pietrov demonstrated heroism near the village of Mantvidowo, for which he was awarded the Order of Saint Anna III class with swords and bow on July 29.

He was appointed as the commissioner to the Kielce Commission for Peasant Affairs (acting from February 17, officially confirmed on September 13).

Pietrov was an adherent of General-Governor Iosif Gurko, advocating for strict treatment of Poles.

At the request of Professor Alexander Brandt, he approved the construction of the Kharkov Zoo and aquarium complex.

His next assignment brought him back to Congress Poland, where he served as the assistant to the general-governor for administering the Vistula Land (preceded by Nikolai Medem and succeeded by Alexander Obolensky).

They had one daughter, Alexandra, born on 21 December 1872, who married artillery colonel Nikolai Aleksandrovich Krutikov.

[12][13] Aleksandr Petrov was awarded the following orders: Pietrov received written commendations from the emperor four times: from Alexander III on 26 April 1882, and from Nicholas II in 1897, 1900, and 1914.

Initially set for six years, this annuity was extended twice, each time for an additional four-year period.