Štefánik was born in Kosaras, Nyitra County, Kingdom of Hungary, Austria-Hungary (now Košariská, Slovakia), on 21 July 1880.

The philosophy lectures were given by Tomáš Garrigue Masaryk, the future first president of Czechoslovakia, who inspired Štefánik with the idea of co-operation between the Czechs and the Slovaks.

His studies were financed largely by Czech associations, including Českoslovanská jednota (Czechoslavic Unity) and Radhošť since he could not afford them himself.

Initially, he had no money and no command of French, but he was nevertheless able to obtain a job at the famous Paris-Meudon Observatory after its director, Pierre Janssen, one of the cofounders of astrophysics, saw Štefánik's talent.

Between 20 June and 4 July 1905, Štefánik climbed Mont Blanc (he did so several more times in the following years) to observe the Moon and Mars.

In 1907, Štefánik received the Prix Jules Janssen, the highest award of the Société astronomique de France, the French astronomical society.

Since 1908, he had been charged by the French authorities with astronomical and meteorological observations, (mainly observations of solar eclipses) and political tasks in various countries all over the world, including (Algeria, Morocco, Turkistan, Russia, India, the United States, Panama, Brazil, Ecuador, Australia, New Zealand, Tahiti, Fiji, and Tonga).

In Tahiti, he also built an observatory and a network of meteorological stations (rumour has it that much of his time in the Pacific Ocean was spent on spying on German positions).

In 1912, a mission from the Bureau des Longitudes, based in France, was led by Milan Rastislav Štefánik, with the assistance of Jaromír Králiček.

They set up in a location near Passa Quatro (Minas Gerais), where they joined the main team of the National Observatory's expedition.

His friends included physicist Henri Poincaré, Aymar de la Baume, Joseph Vallot (the richest man in France), architect Gustave Eiffel, Roland Bonaparte, Prime Minister Camille Chautemps, a French entrepreneur called Devousoud from Chamonix, American astronomer and admiral Simon Newcomb and American diplomat David Jayne Hill.

The Serbian campaign was unsuccessful, but French aviator Louis Paulhan is credited with the world's first "medevac" by flying the seriously-ill Štefánik to safety.

In 1916, the three men founded the Czechoslovak National Council, which led to the government of Czecho-Slovak resistance abroad and to the creation of Czechoslovakia in 1918.

For this purpose, Štefánik, both as the Czechoslovak Minister of War and as a French general, went to Russia in February 1917 and then to the United States, in the meantime he met Thomas Garrigue Masaryk in London in April.

In May 1918 Štefánik went to Siberia to try to rally the Czechoslovak legions to a renewal of the Eastern Front, as Bolshevik Russia had withdrawn from the war by signing the Treaty of Brest-Litovsk with Germany and Austria-Hungary in March 1918.

In January 1919 after the war ended, Štefánik went from Russia to France and Italy, where he organized the March retreat of Czechoslovak troops from Siberia to Paris.

In April, he went from Paris to Rome to negotiate with the Italian Ministry of War, where he met with his fiancée, Juliana Benzoni, for the last time.

Sources do not substantiate rumours of disagreements arising between Štefánik and Beneš or Masaryk, mainly on the position of Slovakia in Czechoslovakia.

To Masaryk, he wrote "with my filial feelings and a great patriotic happiness, I salute you, venerable professor, as the first president of the Czechoslovak Republic".

[7] When Štefánik wanted to return home to see his family, he decided to fly from Campoformido, near Udine, Italy, and to use an Italian military plane, a Caproni Ca.3.

Štefánik died, along with the rest of the crew (two Italian pilots, Colonel Giotto Mancinelli Scotti and Sergeant Umberto Merlino, as well as a mechanic-radiotelegrapher, Gabriel Aggiusto).

At the time of the crash, Vavro Šrobár and his entire government had left Bratislava for Skalica, to plant trees as a memorial to the founding of the new Czechoslovak Republic.

However, the respected Zrínyi Miklós National Defense University in Budapest, in a joint article with the Armed Forces Academy of General Milan Rastislav Štefánik in Slovakia, published a paper, citing the Italian eyewitness First Lieutenant Martinelli-Scotti: "in the course of the first landing attempt, the wheels touched the landing path, after which the cooling water immediately started leaking.