[9][10] In June 1985, under an overseas scholarship awarded by the Public Service Commission, Yong sat for a tripos and graduated from the University of Cambridge with first class honours, obtaining a Bachelor of Arts in economics.
[12] Upon graduation, Yong returned to Singapore and began her career in the Ministry of Trade and Industry (MTI), eventually rising to the position of assistant director.
I do think a certain part of it was due to the changes in personnel management as well — I'm lucky, because I was in the right place at the right time, at the right age!I think the key factor was that I had been doing a superscale job in MTI.
Upon the establishment, Yong announced plans promote the growth and development of infocommunications in Singapore, and reassured industry stakeholders that there will be liberalisation and support provided.
[31][32] Shortly after, on 9 January, Yong was also appointed to the Economic Review Committee, chaired by Minister of State Ng Eng Hen.
[33][34] In September 2003, Yong was the founding chairman of the Workforce Development Agency (WDA), a newly-established statutory board under MOM to promote continuing education and professional training for workers.
[40][41] In January 2007, to foster closer cooperation in healthcare, Yong signed a memorandum of understanding with her Dubai counterpart, Qadhi Saeed Almurooshid.
[47] On 1 April 2012, Yong relinquished her health portfolio and succeeded Lim Soo Hoon as permanent secretary for the public service division.
[52][53] On 1 April 2022, after 36 years in the public service, Yong retired, relinquishing her permanent secretary role for MCI to Joseph Leong.