For his protests against the military government, he spent over 17 years in prison on multiple occasions between 1989 and 2012.

On 28 August 1988, he became the vice-chair of the All Burma Federation of Student Unions (ABSFU) led by Min Ko Naing.

Following his release, he led the ABSFU from July 1989 to December 1991, while his friend and colleague Min Ko Naing remained in detention.

When he completed his prison term, the authorities continued to detain him under section 10(A) of the State Protection Act.

On 27 September 2006, he was arrested, together with Min Ko Naing, Htay Kywe, Min Zeya and Pyone Cho, for their pro-democracy activities, including the White Sunday Campaign, which began in early 2006.

In August 2007, he and other activists from the 88 Generation movement marched to protest against high fuel prices.

The protests led to the Saffron Revolution, largest demonstrations against the military government since 1988.