Sonam Drakpa was the son of Rinchen Dorje, a brother of the regent Jamyang Shakya Gyaltsen. At the age of nine he was elevated to abbot of the Tsethang monastery, succeeding his eldest brother Drakpa Rinchen. In 1381 he took the dignity of regent (desi) of Tibet after the abdication of his other brother Drakpa Changchub. His short rule was considered by the Tibetans to be particularly prosperous, with excellent crops. He was therefore known as "the Fortunate King".
Pushed from power
That the Ming Dynasty had limited insight in Tibetan affairs at this time is indicated by the erroneous statement that Sonam Drakpa directly succeeded his uncle Jamyang Shakya Gyaltsen. Nevertheless, the Chinese titles conferred on various Tibetan lords were evidently valued since they are also mentioned in Tibetan chronicles.
Sonam Drakpa sent a letter to Hongwu, claiming that he was ill and therefore suggested his cousin Drakpa Gyaltsen as his successor. This was endorsed by the Chinese emperor. The abdicated regent withdrew to the monastery Thel. In 1405 he became a kunpang, a person who completely renounces the world. Three years later he died.