In 1918, as a high school student, he joined the Polish municipal militia in Warsaw, organized after the withdrawal of German troops.

[2] In 1926, Jeliński, together with Eugeniusz Smosarski (brother of Jadwiga Smosarska),[3] Brunon Bredschneider (a filmmaker),[4] and Jan Ława (a sailor),[5] and their dog Oranek, organized a trip around the world by car.

[8] The remaining three continued through Sicily to Tunis and Algiers, where Bredschneider ended his journey, finding further travel tiring and unprofitable.

[11] Thanks to his perseverance (he gave many lectures to the Polish diaspora) and the help of Polish Americans,[12] he traveled through the United States (from New York through Washington – where he had an audience with President Coolidge – Pittsburgh, Detroit – from where he continued in a new Buick Master Six[13] – Cleveland, Buffalo, Niagara Falls, Chicago, Milwaukee, Saint Louis, Denver, Los Angeles to San Francisco).

[15] The journey continued by ship Taiyō Maru from Hawaii to Japan, where he traveled from Yokohama to Kobe (through Kamakura, around Mount Fuji, Nikkō, Tokyo, Kyoto, Osaka).

[25] The expedition was described by Władysław Umiński in the book Pod flagą polską samochodem naokoło świata [pl] (Under the Polish Flag: Around the World by Car) published in 1929.