Mr Lee Tzu Yang, 63, will begin his new appointments as member and deputy chairman of PSC from today.
He will be the third deputy chairman in the team - serving alongside Great Eastern Holdings' non-executive director Tan Yam Pin and Singapore Technologies Engineering chairman Kwa Chong Seng.
The commission's chairman is Mr Eddie Teo.
Mr Lee graduated from the London School of Economics and Political Science in 1976, joining Shell three years later.
He retired as chairman of Shell Companies in Singapore in 2014, after 35 years in operational, commercial and strategy functions in a range of markets.
Mr Lee is a member of the Council of Presidential Advisers and the Legal Service Commission of Singapore. He is also a Justice of the Peace and vice-chairman of the Board of Visiting Justices and Board of Inspection.
He also chairs the board of The Esplanade Company as well as the Singapore University of Technology and Design.
He was awarded the Public Service Star in 2005 and the Meritorious Service Medal in 2014 for contributions to public service.
With Mr Lee's appointment, PSC will have 13 members other than Mr Teo.
Under the Constitution of the Republic of Singapore, PSC shall have a chairman and between five and 14 other members.