Since Nov 2009, Toh Sim is the Chief Representative in China for Keppel Corporation. Prior to joining Keppel, Toh Sim was the CEO of Evergro Properties Ltd from July 2006 to Nov 2009. Evergro developed real estate in Tianjin, Jiangyin and Changzhou in China.

    As the CEO of Ascendas China from 1 Jan 2004 to June 2006, Toh Sim was responsible for developing and managing Ascendas' businesses in China. This included business space in Suzhou, Shanghai and Beijing. Toh Sim also initiated the development of Ascendas businesses in several cities in China including Hangzhou, Dalian, Xian, and Nanjing.

    Concurrently, as the CEO of SSTD, the Singapore Consortium and shareholder in the Suzhou Industrial Park (SIP) project from 2001 to Jun 2006, Toh Sim looked after the minority shareholder's interest in the joint venture company China-Singapore Suzhou Industrial Park Dev Co Ltd (CSSD). He was also an executive in CSSD from Aug 1994 to end 2003 in charge of the Engineering Department, Finance and General Administration and also participated in investment promotion for the SIP overseas. In 1996, he led a team to start an international school in the SIP.

    He was awarded the Friend of Jiangsu from Jiangsu Provincial Government and Suzhou Honourary Citizenship from Suzhou Municipal Government in 2002. He also received the Labour Award from Jiangsu Province in 2003 and was awarded Changzhou Honourary Citizenship in 2007.

    Prior to joining CSSD, Toh Sim worked in the civil service in Singapore.

    Awarded a scholarship to study in France, he graduated as a Diplome d' Ingenieur (Engineering degree) in Telecommunications in 1981. He later learnt a MBA course in INSEAD and graduated in 1991.