[12][13] After graduating from NUS in 1994, Chia met Tan Chee Kien, the president of the opposition National Solidarity Party (NSP).

[4] In June 2001, the NSP, under Chia's leadership, joined three other opposition parties (SPP, PKMS and SJP) to form the Singapore Democratic Alliance (SDA).

[14] During his term as a NCMP from 5 November 2001 to 18 April 2006, Chia posed questions in Parliament on various issues, including National Service, HDB flats for singles, bus and train fare subsidies, and organ transplants.

On 22 August 2015, Chia released a statement on Facebook announcing that he had decided not to contest in the 2015 general election because he had received a lot of online criticism for pushing the NSP to renege on its deal to avoid a three-cornered fight in MacPherson SMC.

[15] During the 2020 general election, Chia along with Williamson Lee, Melvyn Chiu and Osman Sulaiman contested in Bishan–Toa Payoh GRC against the PAP team of Ng Eng Hen, Chong Kee Hiong, Chee Hong Tat and Saktiandi Supaat.

[10] In 2003, Chia's wife Doreen, who was then pregnant with their first child, made a police report against her husband, alleging that he had molested their Indonesian domestic helper.

Their helper told the police that she was not forced into posing for the pictures, while Chia publicly admitted to taking the photos, confessing that he had an interest in nude photography.

[19] Chia met his wife, Doreen Chee, during a trip to climb Mount Ophir when they were both studying at the National University of Singapore in the early 1990s.