Tan Sri Richard Malanjum graduated from the MARA Institute of Technology in Shah Alam, Selangor (now known as Universiti Teknologi MARA) as an external student at the University of London and obtained a Bachelor of Laws (LLB) in 1975.
He began his legal career in 1975 upon graduation as an administrative officer cum legal officer with the State Attorney Chambers until 1981 when he resigned to go into private practice. Had a successful legal practice until he was appointed in 1992 as a Judicial Commissioner of the High Court of Sabah and Sarawak. In 1993 he was elevated as a High Court Judge of the High Court of Sabah and Sarawak.
In 2002 he was elevated to the Court of Appeal and thereafter to the Federal Court in 2005. In July 2006 he was appointed the Chief Judge of the High Court of Sabah and Sarawak until his appointment as the Chief Justice of Malaysia in 2018.
Had presented papers in many international and national conferences during his tenure as a Judge.