Drubchen Namkha Gyaltsen was born to Rinchen Sonam and Sonam Drolma. From his earliest years he constantly repeated the six syllable mantra of Avalokiteshvara, and loving kindness and compassion towards beings arose naturally for him. An understanding of the nature of mind and the practices of shiné and lhaktong came forth without effort. He received the novice vows from Lama Rinchen Tsultrim when he was eight years old. At twelve he began to study the Hevajra Tantra. At the age of eighteen, he went west to Cholung and began studying under Khon Rinchen Gyalwang Dragpa. From him he received full ordination and the name Namkha Gyaltsen. He then trained for several years in listening, reflecting and meditating on the teachings of both Sutra and Tantra. He also received teachings and transmissions from many other accomplished lamas, such as Buton Rinchen Drub, Lotsawa Namkha Drag, Taktse Gyaltsen Palzang and the Indian pandita Vanaratna. Eventually he met with his main root lama, Sangye Palzang. He received the complete transmission of the teachings and practices of the Shangpa Kagyu from Sangye Palzang, and soon the clear and irrefutable signs of erudition and realisation appeared. He beheld many different yidam deities face to face, such as Kalachakra, Hayagriva, Avalokiteshvara, Vajrayogini, to name just a few. In his dreams he travelled to many pure realms, where he was welcomed by clouds of dakinis and oceans of Dharma-protectors. His compassion for human and non-human beings was unparalleled.
Once, when Kuklung monastery had been damaged by an earthquake, he assisted his master, Sangye Palzang, in the task of renovating it. He would go on to also renovate the residence of Langri Tangpa, a great Bodhisattva in the lineage of Atisha.
At the age of sixty three he established the hermitage of Ritro Rabten at Cholung. A few years after displaying the first signs of illness, he passed away on a tenth day through performing the transference of consciousness into the space of suchness, merging his mind with dharmakaya. He entrusted the entire transmission of the Shangpa Kagyu lineage to Gyagom Legpa Gyaltsen.