In 1986, he contested in the general election for Sungai Besi parliamentary constested in the general election for Sungai Besi parliamentary constituency in Kuala Lumpur. He was elected as a member of parliament for the first time.
In 1990, he was re-elected for the same constituency in the general election.
In the 6 following general elections in 1995, 1999, 2004, 2008, 2013 and 2018, Tan Kok Wai was elected as the Member of Parliament for Cheras constituency in Kuala Lumpur.
Tan Kok Wai was the former DAP National Chairman (Nov 2017 – March 2022). Previously, he also served as DAP’s Acting National Chairman, National Deputy Chairman, National Vice Chairman, Chairman of the Election Preparation Committee, Member of General Election / State Elections Candidate Selection Committee in 2008, 2013 and 2018, Chairman of the Disciplinary Committee, National Organising Secretary, and National Publicity Secretary, Assistant National Organising Secretary and Assistant National Publicity Secretary.
Tan Kok Wai was appointed Special Envoy of Malaysia to the People's Republic of China as well as the Chairman of Malaysia-China Business Council from August 2018 to March 2020.[2]
In terms of social service, he is currently acting as honorary advisors to numerous NGOs in Federal Territory Kuala Lumpur and Selangor.
Appointment as the Advisor of DAP
On 20 March 2022, at the 17th DAP National Congress, Tan was re-elected into the Central Executive Committee.[3] He was then appointed as Advisor of DAP Malaysia after stepping down as the National Chairman.[4]
Controversies
Proposal to reintroduce local elections
On 17 December 2023, Tan called on the government to reintroduce local elections that were abolished in 1976. He also suggested the elections to be held in Kuala Lumpur first to return voters the 'third ballot paper' (the first ballot paper to elect MPs and the second ballot paper to elect Members of the Legislative Assemblies (MLAs)). Tan attracted criticisms from UMNO and PAS politicians who described the elections as unnecessary and only serve the interests of DAP as the demographics of Kuala Lumpur make up mainly of the Chinese and DAP that enjoys strong Chinese electoral support will be dominant in the elections.