Sunanda Deshapriya was a founding member of the Movement for Inter Racial Justice and Equality (MIRJE) in 1979 and the Movement for the Defence of Democratic Rights (MDDR) in 1981.

However, his life as a social activist started when at a much earlier stage, and he was involved the youth insurrection of 1971 in Sri Lanka. This was also the time he first developed an interest in human rights activism and journalism.
This interest continues till date, and Mr. Deshapriya is not only a founder member of the Free Media Movement (FMM) in 1991, but has functioned as the convenor since 2000. He is also a member of the Editors Guild of Sri Lanka.

He both launched and functioned as the Editor of the weekly newspaper Yukthiya until its closure in 2000. Yukthiya newspaper was instrumental in initiating a discourse on inter racial justice issues in the mainstream media in Sri Lanka.

Mr. Deshapriya is the Editor of the monthly magazine Balaya, a magazine on socio-political and economic issues. He edits bi monthly Saama Vimarshi, a magazine on the peace process and related issues. He is a regular columnist for a leading mainstream Sinhala weekly newspaper, the Lankadeepa, and the weekly alternative newspaper, Ravaya mainly on governance and peace issues.

Mr. Deshapriya has researched on media role in conflict in Sri Lankan context and has presented papers at national as well as international media workshops. He has written and lectured on code of ethics for journalists in Sri Lanka.