Kazimierz Swiatek, an ethnic Pole, was born in 1914 in Estonia. After completing a seminary in Pinsk (now in southern Belarus), he was ordained a priest in 1939 and sent to the parish of Pruzhana in the diocese of Pinsk.

He was arrested by the KGB in April 1941 and imprisoned on death row in Brest. He escaped from prison taking advantage of the confusion caused by the German invasion of the Soviet Union on 22 June 1941, and returned to Pruzhana.

In December 1944, the KGB arrested him for a second time. The following year he was sentenced to 10 years of hard labor in concentration camps and spent nine years in Siberia and the north of the USSR, working in the taiga and mines. After his release in June 1954, he returned to Pinsk.

In 1988 he was named a chaplain of Pope John Paul II. In 1991, he was appointed Archbishop of Minsk-Mahilyou and Apostolic Administrator of Pinsk. John Paul II proclaimed Swiatek cardinal in 1994.

After the Gorbachev-era changes in the Soviet Union and the subsequent proclamation of sovereignty by Belarus, Swiatek reorganized and strengthened the ecclesiastical structures in the territory assigned to him, taking particular steps to reclaim and rebuild churches and to provide formation for the clergy.

The Roman Catholic Church's rebirth in Belarus largely derives from the 130 Polish priests who arrived after the collapse of the Soviet Union.