Yam studied at Hwa Chong Junior College[SUP][4][/SUP] and graduated from the University of New South Wales with a First Class Honours in Engineering and Royal Military College, Duntroon, Australia, with The Queens Medal,[SUP][citation needed][/SUP] on a Singapore Armed Forces scholarship. He also has a Masters in Business Administration degree from the National University of Singapore and a Masters in Public Administration degree from Harvard University.[SUP][5][/SUP]
Yam served in the Republic of Singapore Air Force, writing an article in the Military Journal POINTER,[SUP][6][/SUP] rising to be the chief of staff of the air staff [SUP][7][/SUP] and commanding the ground based air-defence systems, including the new Igla short range surface to air missiles,[SUP][8][/SUP][SUP][9][/SUP] before retiring as a Brigadier-General and entering the Civil Service. He joined the Public Service Division in August 1998 and was appointed the Deputy Secretary (Development) and the CEO & Dean of the Civil Service College.
He was then posted to the Ministry of Transport as Deputy Secretary (Sea & Air) on 1 June 2004 and was appointed chief executive of Land Transport Authority on 11 May 2005. He was also President of the Singapore Youth Flying Club for 8 years from 1998 to 2006.[SUP][10][/SUP] Yam was honoured in 2008 with the Public Administration (Gold) Medal, a top National Day Award.[SUP][11][/SUP]
On May 1, 2010 Mr Yam was appointed CED-designate of the PA and on June 1, 2010 fully assumed the Chief Executive Director (CED) mantle, taking over from the retiring Tan Boon Huat.[SUP][12][/SUP][SUP][13][/SUP][SUP][14][/SUP] His appointment as Returning Officer also took effect on June 1, 2010.ref>http://www.elections.gov.sg/gazette/G_ParE2010/Appointment%20of%20Returning%20Officer%20(PEA).pdf
