In 1902, as a pupil, together with two friends, Stanisław Czarnowski and Bolesław Piechowski, he loved reading Aleksander Majkowski's poem "About electing the sexton in Kościerzyna, or five bachelors and only one girl" ("Jak w Koscérznie koscelnégo obrelë, abo pięc kawalerów a jednô jedynô brutka") and Hieronim Derdowski's work "About Mr Czorliński who went to Puck to get nets" ("Ò Panu Czôrlińsczim, co do Pucka po sécë jachôł"); as Karnowski himself wrote in his diary, the books "aroused his fascination".
[8] He finished his junior high school education in Chojnice by obtaining the Polish school-leaving examination certificate (świadectwo maturalne) on 9 March 1907.
[12] However, it was only the reading of the "Dictionary of the Pomeranian, that is Kashubian, language" ("Słownik języka pomorskiego, czyli kaszubskiego") by Stefan Ramułt, that made "stunning impression" on him.
[15] In the same year, during holidays, in Kościerzyna, Karnowski met Aleksander Majkowski, who was then a man of letters and a socio-political activist (the chairman and founder of the student organisation "Vistula" ("Wisła"), the editor-in-chief of "Gazeta Gdańska" and "Drużba").
[16] The meeting with Karnowski encouraged Majkowski to publish the first issue of "Gryf" which, having reached Pelplin, became the daily topic for discussion among Kashubiologists.
[18] Having passed the examination of rigorosum in 1910 and obtained the scholarship of the Society of Scientific Help for the Youth of West Prussia (Towarzystwo Pomocy Naukowej Dla Młodzieży Prus Zachodnich), he left Pelplin and went to Freiburg for further studies.
[20] During his studies, Karnowski prepared a lot of papers but his most important work of this time was a paper on "The development of the Polish nationality in West Prussia in the 19th century" ("O rozwoju narodowości polskiej w Prusach Zachodnich w XIX stuleciu"), which was then published in "Gryf" under the title "Kashubian People in the Previous Century"[21] ("Ludność kaszubska w ubiegłym stuleciu"), and a volume of verse "Nowotné spiéwë" (Poznań 1910).
[26] In 1913, after passing higher court clerk examination (egzamin na referendarza sądowego), Karnowski started military service in Toruń.
In 1919, he was transferred to the 2nd Division in Wągrowiec, then to Gniezno, and then back to Poznań – to the Main Military Court (Główny Sąd Wojskowy) where he was upgraded to the position of captain.
[30] After the war, in 1920 he worked in Toruń at the position of the chairperson of the State Police Headquarters for the Pomeranian Voivodeship (Komenda Policji Państwowej na województwo pomorskie).
[32] In 1923, he was given a decree of nomination for a judge in the Regional Court of Toruń (Sąd Okręgowy), but as early as on 8 October that year, he was transferred to Czersk, where he was supposed to perform the duties of the chairperson of the Poviat Division in Chojnice (Oddział Powiatowy).
Apart from poetry, Jan Karnowski was a columnist and a journalist; he wrote for "Gryf" and for "Mestwin" that he himself issued; he criticised politicians and careerists who exploited Kashubians.
The role Jan Karnowski played in the history of Kashubia and Pomerania, as professor C. Obracht-Prondzyński writes, is genuinely "hard to overrate".
As he was a person who rendered especially great service to Kashubia and Pomerania, named after him were, inter alia, streets in Gdańsk, Sopot and Szczecin (Wosia Budzysza); a road interchange at a point of Trasa Sucharskiego; a monument in Brusy (1986); an obelisk in front of a house in Czarnowo; and commemorative plaques in Chojnice (1964), Krostkowo (2006) and Czersk.
With reference to calling him "the ideological guardian of Mestwin II's testament" ("stróż ideowy testamentu Mściwoja"), a commemorative plaque was placed in the building of the Court in Chojnice to pay homage to Karnowski.