Vallance graduated in 1992 from the National University of Singapore law school, and started his career as a white-collar-crime investigator with the Commercial Affairs Department (then under the Singapore Ministry of Finance). After Vallance was admitted to the Singapore Bar on 10 April 1996, he joined a mid-sized law firm and practiced in the areas of Banking & Finance, Corporate & Commercial, Credit & Security and Bankruptcy & Insolvency.
In 2000, Vallance moved to another mid-sized law firm where he handled debt recovery/credit litigation for various banks in Singapore, as well as various claims for enforcement of secured loans and mortgages. Vallance’s practice also included general commercial work, drafting agreements, preparing and/or rendering advice on contracts, commercial transactions and real estate leasing matters. In October 2005, together with Francis Guok, Vallance co-founded Quantum Law Corporation, and he continues to practice in these areas.
In addition, Vallance is responsible for directing and managing the day-to-day administration and operations of Quantum Law Corporation.