Despite being an
SAF scholar, Khoo was called to join the
Singapore Police Force (SPF) after a short stint in the
Singapore Armed Forces (SAF). He began his career in 1977 and has held various appointments, including Director of Strategic Planning in 1987, Police Chief of Staff in 1990, Director of
Criminal Investigation Department in 1991 and
Deputy Commissioner of Police in 1995. In July 1997, he was appointed
Commissioner of Police. Khoo held the post for 14 years and was succeeded by Ng Joo Hee on 1 February 2010, taking on a new post of Senior Deputy Secretary at the
Ministry of Home Affairs. In 2017, Khoo was appointed to the
Global Commission on the Stability of Cyberspace, and he served on the commission until its successful conclusion in 2019, participating in the drafting of its eight norms related to
non-aggression in
cyberspace. ==Interpol==