Thien started his career in one of the most prestigious real estate consultancy firms in Malaysia, C.H. Williams, Talhar & Wong Sdn. Bhd. as an Assistant Valuer cum Research Executive.

Since then, Thien has accumulated more than 30 years of experience in the real estate sector. He served as the Director at Incohasil Sdn. Bhd. from 1986 to 2021 and Ascotville Holding Sdn. Bhd. from 2006 to 2021.

On top of that, Thien has extensive experience in retirement planning, health and life insurance, risk management, estate planning, and wealth management. This was gained over his 21-year career with Prudential Assurance Malaysia Bhd and Eastspring Investment Bhd as an authorised agent and unit trust consultant. Thien is also the co-founder of LSL Planners Sdn. Bhd., which offers retail financial solutions to clients, while also providing estate planning services under Rockwills Corporation Sdn. Bhd.