Career
He is known for the first winter ascents of the eight-thousanders: Gasherbrum I and Broad Peak. At the age of 17, he was the youngest person to climb Khan Tengri in alpine-style. On September 30, 2011, together with Artur Hajzer and Tomasz Wolfart he summited Makalu (8463m).
They climbed the mountain without supplementary oxygen.
On July 31, 2012, he summited K2 (8611m) without use of supplemental oxygen. On March 5, 2013 he climbed Broad Peak (8051m) together with Maciej Berbeka, Artur Małek and Tomasz Kowalski.
The climbers separated before the summit, and while Bielecki and Małek reached the camp on descent, Berbeka and Kowalski went missing and were pronounced dead three days later.