Hajzer summitted seven eight-thousanders, several via new routes (Manaslu’s NE face in 1986, Shishapangma’s east ridge in 1987) and made the first winter climb of Annapurna on February 3, 1987.

As a teenager, he acquired the nickname "the elephant" (Słon in Polish) for his climbing ability and endurance.

In 1989, Hajzer organized a successful rescue operation on Mount Everest’s West Ridge for Andrzej Marciniak in 1989, supported by Sherpas Zangbu and Shiwa and New Zealanders Rob Hall and Gary Ball.

[7] Hajzer returned to attempt Lhotse's South Face three times, reaching 8200 m in 1985,[8] 8300 m in 1987[9] and 7200 m (alpine style) in 1989.

[10] In 2005, he returned to climbing, heading first to a summit attempt at Broad Peak, where he broke his leg.

[12] The success of the expedition earned Hajzer considerable esteem, as well as the patronage of Poland's President, Bronislaw Komorowski, for the Polish Winter Himalayan Mountaineering 2010 – 2015 project.