Dr Rainier obtained his Bachelor of Science in Biochemistry in University of the Philippines Manila. He completed his Doctor of Medicine degree in Pamantasan ng Lungsod ng Maynila-PLM (University of the City of Manila). He is a recipient of the Five Most Outstanding Campus Leaders (FOCAL) Award and Tanging Banggit Award for his exemplary contribution to PLM in 2007 and 2008.
He completed his postgraduate internship in Ospital ng Maynila Medical Center (OMMC) in which he was awarded as the Most Outstanding Medical Intern in 2009. He finished his Internal Medicine Residency training in the same institution. He is currently a certified internal medicine fellow of Philippine College of Physicians. He has previously worked as resident physician in Johns Hopkins Singapore Medical Oncology Department and Tan Tock Seng Hospital.
Dr Rainier has vast work experience in both the public and private hospitals as a specialist of Internal Medicine managing acute and chronic diseases in both Singapore and Philippines.
Dr. Rainier is also a research grantee of the Philippine College of Physicians - Manila Chapter in 2014. One of his research studies was on the effect of Moringa oleifera on HsCRP and Hemoglobin A1c levels of diabetic patients. It was published and presented in different medical societies in the Philippines and was also presented in British Medical Journal Forum in Quality and Safety in Healthcare 2015 in Hongkong.
Dr. Rainier is also a founder of organizations like the NAIS Youth Circle and PLM Iskolars Dance Incorporated, the official dance varsity of PLM. He previously held various key positions in different organizations, VP for External Affairs of University of the Philippines Manila Indayog Dance Varsity and the former President of the Brotherhood of Medical Scholars (BMS) in PLM College of Medicine, to mention a few.