The mountain bond was born when Colonel Kumar met Tenzing Norgay, director of the Himalayan Mountaineering Institute, in Darjeeling. In March 1958, Narendra led the successful Army and Navy expedition to Mt. Trisul (23,360 ft). He also scaled Kabru Dome (21,780 ft) in 1959 and Yellow Needle Peak (22,480 ft) in 1960. He was the first Indian to reach up to 28,700 ft, in his first attempt at climbing the Mount Everest in 1960, before having to turn back due to inclement weather. In 1961, Kumar led a harrowing 5-men expedition to climb Neelkanth (21,644 ft) in the Garhwal Himalayas. While descending from the summit,Kumar lost four of his toes due to frostbite and stopped 200m short of the summit. In 1964, he was first Indian to scale Nanda Devi. In 1965, he was deputy leader of a team that put nine Indian Army climbers at the top of the world's tallest peak. Capt. Mohan Singh Kohli, who led the 1965 Everest expedition, said Kumar's climbing career was astonishing. He also scaled Mont Blanc (15,782 ft), the highest peak in the Alps in 1968. In 1970 he led the first recognised ascent of 23,997 ft Jomolhari (Chomo Lhari), the highest mountain in Bhutan. Kumar successfully climbed the Kangchenjunga from the toughest north-east spur in 1977.