The travel grant to Munich allowed him to attend the lectures on art history by Karl Dochlemann and mathematics by Aurel Voss and Alfred Pringsheim.

Bartel gave his habilitation thesis "O płaskich utworach inwolucji stopnia czwartego szeregu zerowego" (On planar products of involution of the fourth series of the zero degree) in 1912,[8] then received the title of associate professor.

Bartel eventually left the party and the organisation in April 1925, along with Marian Zyndram-Kościałkowski and Bolesław Wysłouch and later founded the parliamentary "Labour Club".

Just before the May Coup of 1926, Bartel received an order from Marshal Piłsudski to prepare for a takeover as prime minister after the expected collapse of President Stanisław Wojciechowski and his government.

As prime minister, he tried to aid every man possible, even the men and women that opposed his policies and the government, but he was not able to help himself, which led to his early decline in politics and diplomacy of the Polish Republic.

At the same time, he promised the immediate removal of incompetent and corrupt politicians from any high posts that could negatively influence the future economic growth of the Second Polish Republic.

Bartel's first government was one of the most active in the history of Poland; the politicians and members of parliament gathered every second day and on occasions everyday to discuss political matters.

After his second election, Bartel primarily focused on the restoration of the decree based on the organization of the highest military authorities from 7 January 1921, which enables the free management of the Ministry of War without the vote of the government and the parliament.

At a private meeting with senators, he highlighted his determination and involvement in fighting against bureaucracy, the introduction of an apolitical army and the elimination of the Ministry of Public Works.

He vividly stated that before the May Coupn there was no democracy and that Poland was ruled by an oligarchy, nobles and influential leaders of wealthy privately-owned clubs and parties.

Otherwise the post of the head of government (Prime Minister) was taken by Kazimierz Świtalski or Walery Sławek, both of whom were considered to be uncompromising supporters of the conflict with the parliament.

Bartel demanded such procedures from every minister and senator of his cabinet and personally prepared the agenda for each meeting of the government and disallowed to discuss any topic without his permission or consent."

He was determined to eliminate the remnants of regulations dating back to the times of Tsar Nicholas II of Russia and Congress Poland, focused on the persecution of religious minorities, especially the Jews and the Gypsies.

Bartel's cabinet announced that it is against such inhumane procedures and actions, and in 1927 the Prime Minister gave permission to adopt a law officially recognizing and granting rights to the Jewish communities.

Once more, that was not in violation of the Constitution, but the anti-parliamentarian speakers and the socialist politicians, confused with the frequent changes in the administration and the government, threatened the Sejm and even suggested a rebellion or another coup.

On 27 March the "Nonpartisan Bloc for Cooperation with the Government" (BBWR), an ostensibly non-political organization that existed from 1928 to 1935, closely affiliated with Józef Piłsudski and his Sanacja movement, declared Bartel's candidacy.

The situation worsened in the upcoming months and some ministers raised concerns about their safety, as some demonstrators, often made up of ordinary citizens working on the behalf of the party, tended to physically abuse officials travelling from their homes to the newly constructed government building located on Wiejska Street in Warsaw.

On 29 December 1929, Bartel was chosen for the third time to be prime minister and formed his fifth government and cabinet, however, he performed his duties with large uncertainties, mainly due to poor health.

During his work at the Technical University of Lwów, he expressed strong opposition to plans focused on introducing the so-called "ghetto benches" for students of Jewish origin and ethnicity to separate them from Polish and Christian peers.

In 1932, he testified as a witness in the Brest trials, lasting from 26 October 1931 to 13 January 1932, held at the Warsaw Regional Court where leaders of the Centrolew, a "centre-Left" anti-Sanacja political opposition movement, were tried.

In 1937, Bartel was appointed Senator of Poland by the President to replace the deceased Emil Bobrowski, and served until the outbreak of World War II.

In the autumn of 1938, he was one of the signatories of a document addressed to President Mościcki, which called for the inclusion of representatives of the opposition to the government in connection with the threat of the country's independence.

In it, he sharply criticized the situation in universities and colleges around Poland; mentioned the widespread anti-Semitism there; and the failed organization of studies, subjects and courses.

Conversations and topics mentioned mostly related scientific issues, and Bartel signed a contract with a publishing house to write a textbook of Science and Geometry for the schools of the Soviet Union.

As he wrote to his wife on 16 July 1941: "By listening to private conversations of the officers, I conclude that my position as Prime Minister may be resurrected, but what great duty this will be to control a split, communist country.

In Moscow with Joseph Stalin, I had the pleasure of finding out new information from the West - Winston Churchill's speech addressed to Władysław Sikorski about Poland's supposed future."

Similar information can be found, among others, in a telegram sent by the Polish Chargé d'Affaires in Switzerland to the Ministry of Foreign Affairs in London dating from 26 September 1940: "It's believed that Moscow professor Bartel has intention to create the Red Government of Poland."

The decision was motivated by the political loyalty of the former prime minister, as well as his successful efforts to preserve the Polish character of the Lwów Polytechnic under Soviet occupation.

The guards called him a Commie-Jew, as reported by Stefanowicz, and the Nazi officials ordered Bartel to clean the boots of a Ukrainian Hilfsgestapo soldier.

[6] According to one account, during the night of October 1943 the Sonderkommando composed of Jewish prisoners unearthed the bodies of the murdered Polish professors that were filed in a mass grave.