JohnpauliiKarol Józef Wojtyła was born on 18 May 1920 in the Polish town of Wadowice and was the youngest of three children of Karol Wojtyła, an ethnic Pole and Emilia Kaczorowska; who was of Lithuanian ancestry. Yaakov Wise, Jewish historian, chazzan and scientist from Manchester, holds that Karol's mother was of Jewish ancestry and originally named Emilia Katz, but later polonized her last name. His mother died on April 13, 1929, when he was just nine years old, and his father supported him so that he could study. His brother, who worked as a doctor, died when Wojtyła was twelve. He lost everyone in his family - a sister, brother, mother, and father - before he became a priest. His youth was marked by extensive contacts with the then thriving Jewish community of Wadowice. He played sports during his youth, and was particularly interested in football (soccer) as a goalkeeper.

After completing his studies at the Marcin Wadowita high school in Wadowice, in 1938 Wojtyła enrolled at the Jagiellonian University in Kraków, and in a school for drama. He worked as a volunteer librarian and did compulsory military training in the Academic Legion, but refused to hold or fire a weapon. In his youth he was an athlete, actor and playwright and he learned as many as ten languages during his lifetime, including Latin, Ukrainian, Croatian, Greek, Dutch, Spanish, Portuguese, French, Italian, German, English, Yiddish, Hebrew as well as his native Polish. He also had some facility with Russian.

In 1939, Nazi German occupation forces closed the Jagiellonian University. All able-bodied males had to have a job. From 1940 to 1944 Wojtyła variously worked as a messenger for a restaurant and a manual labourer in a limestone quarry, and then as a salesman for the Solvay chemical factory to avoid being deported to Germany. His father died of a heart attack in 1941. B'nai B'rith and other authorities have said he helped Jews find refuge from the Nazis.

On 29 February 1944, Wojtyła was knocked down by a German truck. In sharp contrast to the harshness normally expected from the occupiers and especially from the racialist officials among them, the German Wehrmacht officers and driver tended him and commandeered a passing truck to get him to a hospital. He spent two weeks there with a severe concussion and a shoulder injury. This accident and his survival seemed to Wojtyła a confirmation of his priestly vocation. On 6 August 1944, "Black Sunday", just after the Warsaw uprising began, the Gestapo rounded up young men in Kraków to avoid a similar uprising. Wojtyła escaped by hiding in the basement of his home as it was searched, then escaped to the Kraków Archbishop's residence, where he stayed until after the war.

On the night of 17 January 1945, the Germans quit the city, and the seminarians reclaimed the ruined seminary. Wojtyła and another seminarian volunteered for the odious task of chopping up and carting away piles of frozen excrement from the lavatories. That month, Wojtyła personally helped a 14-year-old Jewish refugee girl named Edith Zierer who had run away from a Nazi labor camp in Częstochowa. Zierer was attempting to reach her family in Kraków but had collapsed from cold and exhaustion on a train platform in Jędrzejów. No one helped but Wojtyła, who gave her some hot tea and food, personally carried her to a train and accompanied her to Kraków. Zierer credits Wojtyła for saving her life that day. She would not hear of her benefactor again until she read that he was elected as the Pope in 1978.