Loh joined the Singapore Administrative Service in 1995. He has served in various appointments in the Ministry of Foreign Affairs (MFA), including Singapore’s Ambassador to the People’s Republic of China from 2012 to 2019.  

Loh studied at the National University of Singapore under a Singapore Government Local Merit Scholarship and graduated with First Class Honours in Economics in 1995. From 2003 to 2004, Loh attended the Sloan Masters Programme in Stanford University in California, USA, and graduated with a Masters of Science in Management.