Lobsang Tenzin became a monk at Sera Monastery at the age of twelve and, by the age of fourteen, had joined the underground Snow Leopard Organisation, which reportedly had approximately fifty members at Sera Monastery and was headed by Geshe Labring. As part of this network, he was involved in distributing pro-independence pamphlets through various clandestine means across Tibet.

On 3 March 1988, Lobsang Tenzin was arrested for participating in the Monlam Chenmo demonstration. He was only sixteen years old at the time. He was detained for one year without a fair trial; his detention was later extended by an additional year after he resisted a Chinese official who began beating him without provocation.