In 1930, he went to Asia, where he founded friaries in Nagasaki and in India. In 1936, he was recalled to supervise the original friary near Warsaw. When Germany invaded Poland in 1939, he knew that the friary would be seized, and sent most of the friars home. He was imprisoned briefly and then released, and returned to the friary, where he and the other friars began to organize a shelter for 3,000 Polish refugees, among whom were 2,000 Jews. The friars shared everything they had with the refugees. They housed, fed and clothed them, and brought all their machinery into use in their service. Inevitably, the community came under suspicion and was watched closely. Then, in May 1941, the friary was closed down and Maximilian and four companions were taken to Auschwitz, where they worked with the other prisoners, chiefly at carrying logs. Maximilian carried on his priestly work surreptitiously, hearing confessions in unlikely places and celebrating the Lord's Supper.
Maximilian studied at Rome and was ordained in 1919. He returned to Poland and taught Church history in a seminary. He built a friary just west of Warsaw, which eventually housed 762 Franciscans and printed eleven periodicals (one with a circulation of over a million), including a daily newspaper.
To discourage escapes, the camp had a rule that if a man escaped, ten men would be killed in retaliation. In July 1941, a man from Kolbe's bunker escaped. The fugitive has not been found!" the commandant Karl Fritsch screamed. "Ten of you will die for him in the starvation bunker. The ten were selected, including Franciszek Gajowniczek, imprisoned for helping the Polish Resistance. He couldn't help a cry of anguish. "My poor wife!" he sobbed. "My poor children! What will they do?"Maximilian stepped silently forward, took off his cap, and stood before the commandant and said, "I am a Catholic priest. Let me take his place. I am old. He has a wife and children."
Maximilian died on 14 August 1941 by lethal carbonic acid injection after three weeks of starvation and dehydration at the Auschwitz, Poland death camp. He was canonized 10 October 1982 by Pope John Paul II; declared a martyr ofcharity.