Przhevalsky was born in Kimborovo, in the Smolensky Uyezd of the Smolensk Governorate of the Russian Empire into a noble polonized Belarusian or Ukrainian family (Polish name is Przewalski), and studied there and at the military academy in St. Petersburg. In 1864, he became a geography teacher at the military school in Warsaw.

In 1867, Przhevalsky successfully petitioned the Russian Geographical Society to be dispatched to Irkutsk, in central Siberia. His intention was to explore the basin of the Ussuri River, a major tributary of the Amur on the Russian–Chinese frontier. This was his first important expedition. It lasted two years, after which Przhevalsky published a diary of the expedition under the title, Travels in the Ussuri Region, 1867–69.

There is an urban legend that Joseph Stalin was an illegitimate son of Nikolay Przhevalsky. The legend is based on the facial similarity of both men, Stalin’s official birthdate controversy (claims that he was born on 6 December 1878 instead of 21 December 1879,) and that the late Stalin era saw a resurrection of interest to the personality of Przhevalsky, numerous books and monographs were published in the Soviet Union and satellite Communist countries (which was a rare occurrence in regard to the Tzarist-era scientists,) Soviet encyclopedias portrayed Przhevalsky in sharp similarity to Stalin, which was rumored that in such a discreet manner Stalin was paying a homage to his alleged biological father. M. Khachaturova, a Tbilisi resident, who happened to know an unnamed old lady, the original bearer of the secret, was considered to be a whistleblower of the myth about Stalin’s mother alleged promiscuity. Przhevalsky’s diary, if it ever existed, was rumored to disappear from archives during the early days of Stalin’s ascent to power as the Communist party career, especially in its highest echelon, was troublesome for the noble blood people, who claimed a hoi polloi origin. There were unsubstantiated claims that certain 1881 paycheck ledger contained brief notes on money transfer from Przhevalsky to Stalin’s mother. However, Przhevalsky’s visits to Georgia are not recorded, and G. Egnatashvili, a family friend of the Jughashvilis, didn’t recollect anything which could possibly substantiate those claims. During the Stalin era any talk concerning his ancestry and childhood was a public taboo, but the ferocity, with which the legend was debunked after the Stalin’s death with the entire monographs written in order to disprove the myth (up until the 2010s,) also was considered by some as a further proof of veracity of the Przhevalsky’s alleged one-night-stand theory. A humorously developed version of this legend appears in The Life and Extraordinary Adventures of Private Ivan Chonkin (Book Three) by Vladimir Voinovich.

The results of these expanded journeys opened a new era for the study of Central Asian geography as well as studies of the fauna and flora of this immense region that were relatively unknown to his Western contemporaries. Among other things, he described Przewalski’s horse and Przewalski’s gazelle, which were both named after him. He also described what was then considered to be a wild population of Bactrian camel. In the 21st century, the Wild Bactrian camel was shown to be a separate species from the domestic Bactrian camel. Przhevalsky’s writings include five major books written in Russian and two English translations: Mongolia, the Tangut Country, and the Solitudes of Northern Tibet [1] (1875) and From Kulja, Across the Tian Shan to Lob-Nor (1879). The Royal Geographical Society awarded him their Founder’s Gold Medal in 1879 for his work.

There is another place named after Przhevalsky: he had lived in a small village called Sloboda, Smolensk Oblast, Russia from 1881-7 (except the period of his travels) and he apparently loved it. The village was renamed after him in 1964 and is now called Przhevalskoye. There is a memorial complex there that includes the old and new houses of Nikolay Przhevalsky, his bust, pond, garden, birch alleys, and khatka (a lodge, watch-house). This is the only museum of the famous traveler in Russia.