Phu Dorji made history as the first man to climb Mount Everest without supplemental oxygen on May 9, 1984. He accomplished this daring feat via the standard South East Ridge route during an Indian expedition led by Darshan Kumar Khullar. His achievement showcased immense endurance and marked a new milestone in high-altitude mountaineering. It remains one of India's proudest moments in Himalayan exploration.

Earlier, Phu Dorji was part of India's third Everest expedition in 1965, led by Capt. M.S. Kohli. Along with Maj. Bahuguna, Harish Rawat, and HPS Ahluwalia, he successfully reached the summit on May 29, 1965. This climb came after failed attempts in 1960 and 1962 due to harsh weather. Phu Dorji tragically lost his life in May 1987 during the Kanchenjunga expedition with the Assam Rifles.