On the successful K2 expedition, Compagnoni's decision to place the final camp (IX) at a higher location than formerly agreed was a source of controversy.

[1] Bonatti and a Hunza climber, Amir Mehdi, climbed up to deliver oxygen to Compagnoni and Lacedeilli for their summit attempt.

Bonatti and Mehdi arrived in failing light at a point on the "shoulder" at 7,900 metres (26,000 ft) where the team had agreed to place camp IX.

However his motive actually was to prevent Walter Bonatti from reaching the camp and hence join the summit team in an attempt.

At 18:10 the next evening, Compagnoni and Lino Lacedelli reached the summit of K2, using the supplemental oxygen Bonatti and Mehdi had brought them.

[5] During his service with the Alpini corps of the Italian army, he participated together with Lieutenant Giuseppe Lamberti and Sergeant Ettore Schranz in the fourth edition of the legendary Trofeo Mezzalama, when their team placed second.

[6][7] Further notable results were: 1st Class / Knight Grand Cross: Cavaliere di Gran Croce Ordine al Merito della Repubblica Italiana (8,362)