The younger of his parents' two sons, Jerzy was brought up in Harbin where his parents enjoyed a good life style since his father Stanisław was well paid being promoted to colonel in 1912 and commander of a battalion in the 35th Siberian Rifle Regiment in 1914. Jerzy's childhood was a time of great joy growing up in an environment with mixed races and nations, all with their different languages and customs, cultures and religions. He did not attend school in Harbin but was educated at home up to the age of 15. At this time he was sent to Tyumen to attend secondary school there. Tyumen is on the Trans-Siberian Railway, where it crosses the Tura River, about 300 km east of Yekaterinburg. Although connected to Harbin by the Trans-Siberian Railway, the two towns are an enormous distance apart, namely about 4500 km by rail. In October 1917 the Russian Revolution saw the tsar, Nicholas II, deposed and in July 1918 he was executed in Yekaterinburg. Jerzy's parents felt that their son would be safer if he were with them in Harbin so he returned there in 1918. His father had been released from military service with the Soviet authorities in January 1918. However, the end of World War I ended over 100 years of Poland being partitioned between the three major powers, and the Polish Republic was restored on 11 November 1918.
With Poland existing again as an independent country, the Słupecki family decided to return from Harbin to their own country. This, however, proved not to be easy and only Stanisław Słupecki managed to return at this time and he joined the Polish army in December 1918. Szczęsna Słupecka and her two sons failed in their attempt to return to Poland and were forced to remain in Siberia from 1918 to 1921. The conditions were harsh and Jerzy's brother contracted tuberculosis. Jerzy himself suffered poor health but had to work to support the family financially. Eventually, in 1921, all the family returned to Warsaw where Jerzy was able to continue his much interrupted education.
Słupecki had lost at least three years of secondary education but he was able to pass the grade four examinations and was admitted to the Tadeusz Rejtan VI State High School in Warsaw. This school, founded in 1905, was one of the best schools in Warsaw. Słupecki graduated from this High School in 1926 and, later in the same year, entered the Warsaw Technical University where he studied his favourite subject, namely architecture. Sadly, his health had suffered during the Siberian winters and he now had a lung infection which forced him to terminate his studies of architecture. After some improvement in his health, he decided to study mathematics at Warsaw University. Mathematics had always been a second favourite for Słupecki but, later in life when he was enjoying a highly successful career, he still regretted having to give up studying architecture.
Once again Słupecki encountered unfortunate difficulties with his studies at Warsaw University. His father Stanisław had retired in 1923, by which time he was a Brigadier General in the Polish Army, and died in Warsaw on 24 November 1929. Suddenly the family, who had always been well off, were in financial difficulties. Słupecki tried to help out the family finances with a variety of different jobs, some with the Warsaw Municipal Council and some with the Historical Museum. The consequence was that up to 1932 he had little time to devote to his mathematical studies and only in 1932 was he able to resume these studies with the attention that he wanted to give them. His mathematics professors at Warsaw University included Kazimierz Kuratowski, Stanisław Leśniewski, Stefan Mazurkiewicz, Jan Łukasiewicz, Wacław Sierpiński, Adolf Lindenbaum and Alfred Tarski. Adolf Lindenbaum was only two months older than Słupecki but had been awarded a doctorate in 1928, the difference being simply a consequence of the problems which had hindered Słupecki's education. Also Tarski, who was only two years older than Słupecki, had been teaching at Warsaw university since 1925.
As well as the important influence of these lecturers, an equally important influence on Słupecki from this time on was Andrzej Mostowski. Mostowski was nine years younger than Słupecki but had begun his studies at Warsaw University in 1931. Słupecki and Mostowski met regularly in Lourse's Café in Krakowskie Przedmieście, one of the most prestigious streets in Warsaw. Other friends who met with them in this café included the mathematics students Stanisław Hartman (1914-1992) and Julian Perkal (1913-1965). The authors of  write:-
It was a difficult time in the academic life of Poland, especially in Warsaw. Right-wing political organizations ventured a harsh anti-Semitic campaign and the leadership of the Mathematical-Physical Club of the students of the Warsaw University decided to expel the students of Jewish origin. Słupecki and his friends firmly opposed the anti-Semitic measures; Jerzy, because he was considerably older than his fellow-students, was in a sense an authority among his friendsIt was during these years when he studied in Warsaw that Słupecki's interests turned towards mathematical logic. In many ways this is not surprising since it was a period when the Polish School of Logic, based in Warsaw, was flourishing and transmitting enthusiasm to students. Słupecki graduated with a Master's degree from the University of Warsaw in 1935 having written a thesis advised by Jan Łukasiewicz. Słupecki's thesis was outstanding and it received the Department Council's award. Although he would have wished to remain at the University of Warsaw and study there for his doctorate, this was not possible in a situation where, despite having a school of extraordinary talents, it was not possible to employ someone as gifted as Słupecki. He therefore took a position as a mathematics teacher at the Curie-Skłodowska State Gymnasium in Warsaw which allowed him to continue to be a part of the Warsaw School of Logic. With Łukasiewicz as his research advisor, Słupecki worked on his doctoral thesis while being a full-time secondary school teacher.
In 1937 he married Stanisława Izydorzak. In the following year he submitted his thesis A proof of the axiomatizability of full systems of many-valued propositional calculus (Polish) and was awarded a Ph.D. Wacław Sierpiński was an examiner of Słupecki's thesis. In his student days he had met with friends in Lourse's Café in Krakowskie Przedmieście, but now, in addition to his friends, he met the professors from the university, in particular Łukasiewicz and Leśniewski. The life of all these people soon changed dramatically with the outbreak of World War II.
On 1 September 1939 German troops entered Poland and the German Luftwaffe began bombing all strategically important sites. By 4 September they were within 60 km of Warsaw which they encircled with two pincer movements coming from the north and south, one to the east of Warsaw the other to the west. On 22 September, Russian troops entered Poland occupying Lwów and on 27 September Warsaw surrendered. The Germans and Russians had agreed to partition Poland between them and this now came about. Warsaw was occupied by the Germans who closed the University of Warsaw. The university buildings became a military barracks. In fact the Germans closed all higher education establishments in Poland for their idea was that they would make use of Poles to carry out their menial tasks so there was no need to educate them.
Although education was now banned in Poland, and punishable by death, many risked their lives to educate young people in secret. In particular Helena Rzeszotarska (1879-1976) ran an underground Gymnasium to teach young people and Słupecki taught in this school. Helena, the daughter of the metallurgist Alfons Jan Kapiston Rzeszotarski who was a professor at St Petersburg, had operated a girls' school for poor families in Warsaw since before World War I. During the German occupation it operated in secret.
Although the buildings of the University of Warsaw had become a military barracks, many of the professors risked their lives continuing to run clandestine lectures for their students. Słupecki taught in this underground university along with several of his friends and teachers such as Łukasiewicz and Mostowski. In addition to these highly dangerous teaching duties, Słupecki also took part in the Konrad Żegota Committee, part of the Polish Resistance. This organisation was set up on 27 September 1942 to help Jews in German occupied Poland. It helped find places of safety for Jews and provided them with aid. Although it operated in several Polish cities, the largest part of the organisation was in Warsaw. It managed to get aid to around one third of the Jews trapped in Warsaw. The authors of  write:-
He regarded his conspiratory activities in the underground during the years of war as something very important, perhaps even the most important, in his life. He was preparing for the Warsaw Uprising in Praga - the right-bank district of the city, but as is well known, German troops brought the situation under control in this part of the city.Many Poles were forced to undertake work for the Germans and, in mid-August 1944, Słupecki was sent to Germany as a labourer. In December, seeing that his health was not good enough to give the Germans the hard labour required, they sent him back to Warsaw. There he undertook a few odd jobs before the city was liberated. On 17 January 1945 Warsaw was liberated by Russian troops but at this stage, with the city and university largely destroyed, it was unclear whether the city and its university would be rebuilt. However staff and students who had survived the war began returning to the university. Słupecki volunteered to teach at the School of Telecommunications in the Praga district of Warsaw and he also taught at the Curie-Skłodowska State Gymnasium, back in the position he had held before the German invasion.
Later in 1945 Słupecki was appointed as an Assistant Professor at the University of Lublin. He worked on his habilitation thesis and he presented From the investigations into Aristotle's syllogistic (Polish) to the Jagiellonian University in Kraków, which led to his appointment as an Extraordinary Professor of Logic and Methodology of Science at Wrocław University and at Wrocław Polytechnic. He continued to hold positions at Wrocław University until he retired in 1974, becoming a full professor there from 1962.
Details of Słupecki's research papers are given in  and we refer the reader there for details. We give a summary of his contributions :-
... the creative work of Jerzy Słupecki comprised five areas: (1) many-valued sentential calculi, (2) theory of deductive systems including metalogic of classical and non-classical logic and the consequence operation of rejection, (3) history of logic (i.e. modern investigations onto the syllogistic of Aristotle), (4) Leśniewski's systems, and (5) didactics of logic and mathematics. Słupecki was conscious of the aim of his logical investigations as consisting in continuation, ramification and popularization of the logical investigations of his masters from the Warsaw school.Słupecki was also the author of a number of books co-authored with colleagues and students.
At Wrocław University, Słupecki was Dean of the Faculty of Mathematics, Physics and Chemistry in 1953-55. He became a full professor in 1962 when he headed the Department of Logic and Methodology. Later this was renamed the Department of Mathematical Logic and Methodology of Teaching Mathematics. However, from 1950 this was only one of Słupecki's two positions and perhaps the one that interested him the least. In 1950 he was appointed to the Higher Pedagogical School in Wrocław. Four years later, this School moved to Opole, a city which had only been returned to Poland in 1945. At this time the city was German but returning it to Poland saw the largely German population slowly replaced by a Polish one. On the Oder river, Opole was both a river port and important place on the railway from Wrocław to Upper Silesia. Słupecki certainly considered his work in Opole to be his most important contribution and in this, despite making many other significant contributions, he was probably correct. Let us quote from the article  on the Opole website:-
He was a co-founder of Opole Pedagogical University and a tireless experimenter in teaching mathematics. He served as chair of the foundations of mathematics at the University of Opole for nearly 20 years, and in the years 1962-1966, as Rector of the Higher Pedagogical School, contributed much to the strengthening of human resources, bringing it on the road to becoming the University of Opole. Słupecki is considered the spiritual father and founder of mathematics and logic at the university in Opole. In Opole he educated dozens of masters, doctors and assistant professors. ... Jerzy Słupecki was the author of many articles in an encyclopaedia and was a great populariser of mathematical logic. He edited the journal "Studia Logica" and a newsletter for teachers "Mathematics". Together with the Opole logicians and mathematicians he developed many lecture notes and textbooks, and actively participated in the work of the Opole Society of Friends of Science. He lectured and organised seminars. He liked our city. Here he had devoted friends, and his own colleagues, who helped him achieve great esteem. He was associated with Opole for over 30 years.Let us end this biography by quoting from :-
When on the cold morning of 21 January 1987, we took our final leave from Jerzy Słupecki, it must have occurred to many participants of that sad ceremony that they were witnessing literally the end of the Warsaw school of logic. ... Słupecki was the last Warsaw logician alive who began his scientific career in the golden twenty years of Polish logic (1919-1939).
Article by: J J O'Connor and E F Robertson