He was a recipient of multiple military and civilian honours including the Param Vishisht Seva Medal, Kirti Chakra, and the Padma Shri.

[10] At the Joint Services Wing (then at the Indian Military Academy in Dehradun) he earned his nickname "Bull," during a boxing match against a senior cadet, Sunith Francis Rodrigues, later the Chief of the Army Staff.

After getting in, and with the Principal out on an expedition, Kumar was under Tenzing Norgay, one of the first two individuals known to ascend Mount Everest, who looked after the course as Director of Field Training.

When the Director of Military Intelligence got to know that the Principal of HMI was undertaking an expedition with foreign money, he stopped the entire program.

General Thimayya crowdfunded the money, making Kumar rather unpopular at the time at his Regimental Centre.

A pre-expedition climb helped select the final team for the ascent and Kumar made it to the first list.

[10] Kumar was the deputy leader of a nine-member Indian Everest Expedition in 1965, that successfully summited the mountain.

[7][10] In 1970 he led the first recognised ascent of [23,997 feet (7,314 m)] Jomolhari (Chomo Lhari), the highest mountain in Bhutan.

[20] On 9 June 1966, by now an acting major, Kumar was appointed Principal of the Himalayan Mountaineering Institute, with the local rank of lieutenant-colonel.

[23] In 1977, Kumar led the first successful ascent of the Kangchenjunga, the third highest mountain in the world, from the north eastern side.

[26][27][19] He wrote in the American Alpine Club's publication that the team consisted entirely of personnel from the Indian Army – sixteen climbers and two doctors.

[24] On 31 May 1977, two men from the team, Major Prem Chand and Naik Nima Dorje Sherpa reached the summit.

[28] In 1981, he was a member of the Antarctica Task Force, chartered with acclimatising and training the first Indian expedition to the continent, led by S. Z. Qasim, in 1982.

[10] He also became the commandant of the Gulmarg based High Altitude Warfare School and Principal of the Himalayan Mountaineering Institute.

[5] Kumar's mountaineering efforts on the Siachen Glacier began when he was approached by a German rafter, in 1977, to help him with a descent on the Nubra river.

At this time Kumar was the commanding officer of the Indian Army's High Altitude Warfare School.

[39] Kumar published accounts of his expeditions in the news magazine The Illustrated Weekly of India, as well as reports in the Himalayan Journal (see Writings).

[43][44][45] Crediting Kumar's contributions being instrumental in the Indian Army's efforts to ending Pakistan's occupation of the glacier, Lieutenant General V. R. Raghavan, commanding officer of the operation, called him 'a mountain of information'.

[47][48] Their son, Akshay Kumar (1969–2020), ran Mercury Himalayan Explorations, an adventure travel and rafting company.

[56] In 2010, he was presented the MacGregor Medal, by the United Service Institution of India, for his military reconnaissance and exploration efforts of remote Indian areas between 1978 and 1981.