This was one act that was to change his life forever and set him on a momentous journey towards the leadership of the Gorkha Janmukti Morcha.

From 1999 to early 2007, he dedicated his service to medically deprived patients with cardiac, carcinoma, hemolytic, nephrotic and neurotic ailments.

In the year 2007, a new political party in name of Gorkha Janmukti Morcha was formed and he was the Press and Publicity Secretary until the 10 August 2009.

For the cause of Gorkhas, he along with his co-leaders and activists participated in fast unto death (hunger) strike in front of District Magistrate Office, Darjeeling for 9 days in the year 2012.

[5] Gurung's GJM was demanding a separate Gorkha state and in 2017 a massive agitation began which also turned violent.

In September 2017, the West Bengal Government appointed the Gorkha Janmukti Morcha (GJM) leader Binay Tamang as the chairman of a new board of administrators to run the Darjeeling hills.

[12][13] Tamang stepped down as the Chairman of GTA and fought the State Assembly By-election as an independent candidate with the support of AITC, but he lost the election.

During the visit of the then Prime Minister of India Late Morarji Desai to Darjeeling, Binoy Tamang was detained by Darjeeling Sadar Police because he showed him his Black Naughty Boy Shoe (the then PM Morarji Desai deliberately made the statement that the Nepali language is a foreign language and Nepalis are foreigners).

[19][20] Leaders of the Gurung faction had earlier promised to back the TMC in the rest of the 14 seats in Darjeeling, Jalpaiguri and Alipurduar districts.

[43][44][45] Binay Tamang, who had won the 2022 GTA election on a TMC ticket but had left that party afterwards, joined Congress on 26 November 2023.