He was the son of Elek Nopcsa [hu] (1848-1918), a member of the Hungarian Parliament and his wife, Matylda Henrietta Żeleński z Żelanki (1852-1938).

In 1895 Nopcsa's younger sister Ilona discovered dinosaur bones at the family estate at Szacsal (today part of Sânpetru, Sântămăria-Orlea, Romania).

Nopcsa volunteered, suggesting he would use money he would gain from marrying a rich American girl to fund the war efforts, however, to no avail.

[12][13] Later, during the First World War, Nopcsa was on another mission as a spy for Austria-Hungary, working undercover as a shepherd in Transylvania.

His motive for aircraft hijacking was to flee the nascent and ultimately short-lived Hungarian Soviet Republic in 1919 to Vienna.

He went to Europe on a motorcycle journey together with his long-standing Albanian secretary and lover Bajazid Elmaz Doda to study fossils.

Finally, in 1933, he fatally shot first his partner, Bayazid Elmas Doda, after having slipped sleeping powder into his tea.

In his suicide note, he describes his reasons for killing his partner:[1] The reason that I shot my longtime friend and secretary, Mr Bayazid Elmas Doda, in his sleep without his suspecting at all is that I did not wish to leave him behind sick, in misery and without a penny, because he would have suffered too much.Nopcsa left behind a considerable quantity of scientific publications and private diaries.

In his diaries he nonchalantly wrote about his bid to become king of Albania:[20] Once a reigning European monarch, I would have no difficulty coming up with the further funds needed by marrying a wealthy American heiress aspiring to royalty, a step which under other circumstances I would have been loath to take.

[7] Only in 2001 was it published in German and it was later translated to English in 2014 as Traveler, Scholar, Political Adventurer: A Transylvanian Baron at the Birth of Albanian Independence, edited by Robert Elsie.

At a time when paleontologists were mainly interested in assembling bones, he tried to deduce the physiology and living behavior of the dinosaurs he was studying.

[24] This theory found favor in the 1960s and later gained wide acceptance, though later fossil finds of tree-living feathered dinosaurs suggest the development of flight may have been more complex than Nopcsa envisioned.

For example, he unearthed six-meter-long sauropods, a group of dinosaurs which elsewhere commonly grew to 30 meters or more, which he named Magyarosaurus.

[25] He theorized that "limited resources" found on islands commonly have an effect of "reducing the size of animals" over the generations, producing a localized form of dwarfism.

[9] During his lifetime Nopcsa published more than fifty scientific studies concerning Albania, covering a wide range of linguistics, folklore, ethnology, history and kanun (that is, Albanian customary law).

[1][40] He left the Albanological part of his estate along with a letter of manuscripts to be published to Norbert Jokl, a renowned specialist in Albanian studies and Nopcsa's former colleague.

When Frashëri was forced to flee the country, Nopcsa's materials were confiscated by the communist regime of Enver Hoxha.

[1] Eventually, Nopcsa's manuscripts, drawings, and completed writings formed the core of the Albanological section of Albania's National Library.