Rahimatsah was born in Tg. Aru, Sabah in 1958. He had his early education at Sacred Heart Primary School in Kota Kinabalu and St. John’s Primary School in Beaufort. He completed his Senior Cambridge Examination at St. John’s Secondary School, Beaufort in 1974 and eventually obtained his doctorate in Planning and Management of Protected Areas at Universiti Teknologi Malaysia (UTM), Johor in 2003.

Rahimatsah is a Fellow of the Academy of Sciences Malaysia (FASc), a Fellow of the Malaysian Scientific Association (FMSA), and Member of the World Commission on Protected Areas (IUCN-WCPA).

He has worked at both national and international levels, from being the General Manager with the State Tourism Action Council (under Ministry of Tourism, Malaysia) to managing projects under DANCED/DANIDA, among others. His last position was as Chief Technical Officer (Borneo Programme) with WWF-Malaysia for 6 years plus until January 2012.

At the state level, he plays an active role as a former Member of the Sabah Biodiversity Council (SaBC); Sabah Environmental Protection Council (SEPC); Deputy President of Sabah Wetlands Conservation Society and internationally as an Executive Committee of the Transboundary Conservation Specialist Group (TBC-SG) and member of the Tourism & Protected Areas Specialist Group (TAPAS Group) of IUCN-WCPA. Currently, he is Member of the Sabah’s Science, Technology & Innovation Council and a Technical Working Committee Member for the Working Group on AFOLU-LULUF in Sabah. 

Rahimatsah continues to play an active role in conservation as a Life member of Malaysian Nature Society (MNS) and the Sabah Wetlands Conservation Society (SWCS). He is an alumni member of Strathclyde University, Universiti Teknologi Malaysia and St. John’s School Alumni Association (Beaufort).

For his service to the state of Perlis, he was awarded the Ahli Mahkota Perlis (AMP) in conjunction with the 62nd birthday of HRH the Raja of Perlis on 17th May 2005.