In 1917-1925, he studied at the Faculty of Architecture of the Warsaw University of Technology, under Edmund Bartłomiejczyk and Edward Wittig. He went on to study painting at the Paris-based École Supérieur des Beaux-Arts. While in Paris, he befriended Mojżesz Kisling and Roman Kramsztyk. He worked as a visual designer for Pro Arte et Studio (starting 1916), Skamander (starting 1920), and Życie Literackie (starting 1924), and as an illustrator for the high-life magazines Pani, Reklama, Teatr i Życie Wytworne, and Arkady. He also worked as a visual artist for publishers, including Ignis, Towarzystwo Wydawnicze Rój, Nasza Księgarnia, Biblioteka Groszowa, and Biblioteka Polska. He was widely recognised as the designer of advertisements for numerous companies, including Wedel, Orbis, Herse, and Schicht. In 1929, Gronowski designed the logo for the LOT Polish Airlines, which has been used to this day. The artist also worked on post stamp design. In 1923, he joined the ‘Rhythm’ Association of Polish Artists. In 1928, he participated in the polychrome work on the Old Town tenement houses in Warsaw. In 1918-1939, he was the artistic manager at the Wierzbicki Printing House, and in 1930-1935, at the Koźmiński Brothers Printing House. He also cooperated with Władysław Główczewski’s Artistic Lithography Workshop. Together with A. Borman, J. Gelbard, J. Mucharski, he opened the artistic advertising studio Plakat. In 1933, he co-founded the Commercial Graphic Artists' Circle. He was also a member of the Association of Polish Artists and Designers, where he co-edited the Association’s magazine, Grafika.