He made his political debut in the 2020 general election as part of a five-member PAP team and won about 57% of the vote in Marine Parade GRC.

[5] Tan funded his university education all by himself, with an annual school fee of S$3,000,[5] by tutoring junior college students in subjects like mathematics, biology, physics and chemistry.

[9] In 2004, Tan joined Parkway Holdings as the chief operating officer of Mount Elizabeth Hospital[10] and was eventually promoted to as the executive director of Pantai Holdings, chief executive officer of Pantai Hospitals Division and the head of Malaysia operating division of Parkway until 2008.

[14] Over the years, Tan has held numerous ministerial advisory and medical committee appointments.

[16] In November 2013, he was appointed by the Ministry of Health as a member of the MediShield Life review committee.

From 2011 to 2019, he was adjunct assistant professor of Duke-NUS Graduate Medical School Singapore, Office of Education.

[18] He has also sat on the Advisory Board of Lee Kong Chian School of Business at Singapore Management University.

[20] Tan was fielded in the 2020 general election to succeed former prime minister Goh Chok Tong who retired from politics, as part of a five-member PAP team contesting in Marine Parade GRC and won.