[5] She made her political debut in the 2015 general election as part of a six-member PAP team contesting in Pasir Ris–Punggol GRC and won 72.89% of the vote.

Having been encouraged by her grandmother to help the needy, she started doing volunteering work in 2001,[8][6][9] while she was studying at the National University of Singapore, from which she graduated with a Bachelor of Social Sciences degree in economics.

[5] [11][12][13] Sun was introduced by the People's Action Party (PAP) as a candidate contesting in Pasir Ris–Punggol GRC on 1 August 2015 in the lead-up to the 2015 general election.

[6][9][14][15][16][17][18][excessive citations] During the campaigning period for the 2015 general election, Sun was the target of xenophobic comments online because her name, which is in hanyu pinyin,[7] misled people into thinking that she was a new Singaporean citizen originally from China.

[2] During the 2020 general election, Sun contested as a solo PAP candidate in Punggol West SMC, which was previously part of Pasir Ris–Punggol GRC.