Gyalzen Norbu took part in the French Himalayan expedition to Makalu 8,485 m (27,838 ft) in 1955 as Sirdar. The team made the first ascent of the mountain on 15 May 1955 (via the north face and east ridge), Lionel Terray and Jean Couzy were the first to reach the summit. The following day Guido Magnone [fr] and Gyalzen Norbu reached the summit. Another four French members of the team summited on 17 May.[3][4]
He climbed on Manaslu 8,163 m (26,781 ft) with Japanese parties in every year from 1952 to 1956[2](p48) and he was Sirdar for the Japanese expedition in 1956. The 1956 expedition leader Maki Yūkō, speaking of Gyalzen, expressed the view that "being head of the Sherpas he was treated as one of the climbing party" and he was one of the two people in the first team to attempt the summit. On 9 May he and Toshio Imanishi [ja] made the first ascent of the mountain.[3][5][6]
In 1956 he was awarded a Tiger Badge by the Himalayan Club for his part in the 1955 French expedition to Makalu, his 'Himalayan Club Number' was 145.[7]