He is an activist of the United Front for Democracy Against Dictatorship (UDD), colloquially known as "Red Shirts" and since 2011 a member of parliament for the Pheu Thai Party.

Born into a family of poor Chinese immigrants, Weng Tojirakarn was admitted to the prestigious Triam Udom Suksa School for his outstanding intelligence.

In particular, he criticised the "custom-tailored" law that allowed Thaksin and his family to sell multi-billion baht shares of their company Shin Corp to investors from Singapore without paying taxes.

The anti-Thaksin movement became the People's Alliance for Democracy (PAD), commonly known as "Yellow Shirts", but Weng became increasingly alienated from the demands of his political friends.

[3] After the 2006 Thai coup d'état that ousted Prime Minister Thaksin and installed a military-backed government, Weng joined the opposite political camp, the pro-Thaksin "Red Shirts".