Up to 16 years he lived with his parents in a village where he did not receive a systematic education: By nature, Obolyaninov was a very intelligent man, with quick consideration, but he was little learned, so he barely knew how to write.

After the accession of Paul, he became one of the closest confidants of the emperor; the royal favors followed one after another: in 1797 he was granted an estate in the Saratov province with 2 thousand souls, the next year he was promoted, became a lieutenant general, in 1799 he was appointed senator.

Without mental and moral culture, deprived of at least practical service experience, Obolyaninov could hold in his post only with unquestioning obedience and precise performance.

The lack of upbringing and education affected the work at the highest post: he often scolded his subordinates, not being embarrassed in expressions; wrote with errors, distorting the name.

Here, at first, he was forbidden even to visit a noble assembly, where Field Marshal Kamensky publicly called him "a state thief, a bribe taker, a fool stuffed".

In this post, he even showed civil courage in 1826, raising his voice for the mitigation of punishment to Muscovite Decembrist Prince Yevgeny Obolensky, who was originally sentenced to the death penalty, then replaced by hard labor.

According to the testimony of the mistress of the neighboring estate:[1] Obolyaninov's face was very ugly: thin, big onion nose, sunken eyes with a stern look, hair very sparse on the whole head and cut out so tightly that it was impossible to catch it.

From January 19, 1795, he was married to Anna Alexandrovna Nashchokina, née Yermolayeva (1754–1822), widow of court counselor Yakov Ivanovich Ordin-Nashchokin (1728–1793); the daughter of Lieutenant Alexander Petrovich Ermolaev and Ekaterina Gavrilovna Belkina.

Since her second marriage was childless, Obolyaninovo near Moscow was inherited by Peter Khrisanfovich's nephew – Lieutenant Colonel Mikhail Mikhailovich Obolyaninov, whose daughter and heiress Anna married Count Adam Olsufyev.