She and her future husband, Kyaw Min Yu (better known as "Ko Jimmy"), participated in 1988's pro-democracy 8888 Uprising, opposing the continued rule of the military dictatorship State Law and Order Restoration Council (SLORC).

In August 2007, anti-government protests (popularly known as the "Saffron Revolution" for the prominent involvement of Buddhist monks)[7] broke out in Yangon in response to increasing fuel and commodity prices.

[8] In May, Nilar Thein had given birth to a baby girl, Phyu Nay Kyi Min Yu, and when hiding with the infant became too difficult, she left the child with in-laws.

[6][8] She then evaded capture for a little more than a year, changing locations and cell phone numbers frequently to avoid detection; she told a reporter that at one point in this period she escaped arrest in a rickshaw taxi.

[9] On 19 June 2008, Nilar Thein published an editorial in the English-language Thai newspaper The Nation, protesting the Burmese government's treatment of women and children.

She was subsequently among a group of 88 Generation Peace and Open Society activists appearing at a press conference, 13 September 2017, at which they issued a written statement that denied the version of events depicted in prominent international media, and in which one of the group's principal figures issued a statement essentially siding with Myanmar's civilian government in its harsh treatment of the Rohingya community.