[1] As an activist, Sidek organised a demonstration outside the Ministry of Education for better salaries for Malay language teachers in the 1960s.
[5] In 1976, then Prime Minister Lee Kuan Yew invited Sidek to join the People's Action Party and contest as a candidate in the upcoming elections.
[9] In 1991, Sidek joined the PAP team for Eunos GRC, switching places with Zulkifli bin Mohammed.
[9] Following the redrawing of boundaries for the 1997 General Election, Sidek was part of the PAP team contesting Aljunied GRC.
The PAP team included future Foreign Minister George Yeo and Ker Sin Tze.
[5][12] He became Parliamentary Secretary for Trade and Industry and Social Affairs in the fifth Lee Kuan Yew cabinet.