Yacob was a member of the country's governing (PAP), she was the ninth Speaker of Parliament, from January 2013 to August 2017. She was a Member of Parliament (MP) representing Jurong Group Representation Constituency between 2001 and 2015, and Marsiling-Yew Tee Group Representation Constituency between 2015 and 2017. On 7 August 2017, she resigned from her positions as Speaker and MP, and from her membership in the PAP, to stand as a candidate for the 2017 Singapore presidential election.