Chelva Rajah has been seconded from the Ministry of Education (MOE) since 2010 as a History educator and teaches pre-service, in-service and postgraduate courses in History. He has 23 years of classroom teaching experience in schools and his main teaching subjects were History and Social Studies. He also held different leadership appointments as a Head of Department such as Discipline, Humanities and Pastoral Care & Career Guidance.
He was previously seconded to the History Unit, Curriculum Planning & Development Department, MOE from 2001 to 2003. He has also been an active member of the History Association of Singapore since 2003. He takes a keen interest in local history and field trips.