Obtained both his Bachelor of Arts and Bachelor of Law degrees from the University of the Philippines, and his Master in Comparative Law from George Washington University in Washington DC, USA. He has been active in the practice of law for over thirty years and is also licensed to practise law in New York, USA. A lecturer and writer,he has written and published articles in taxation, environment and commercial law.
He is an active member of LAWASIA, the law association for Asia and the Pacific. The association, originally composed of 25 member countries, has now accepted new members from Europe and other neighbouring countries. He has served as Philippine Council member in the LAWASIA Council for several terms. From among the members of LAWASIA (as the forerunners), the League of Lawyers Organisation was conceived and established which now includes among its members distinguished law firms and lawyers from the Asia Pacific region and Europe.
Mr Tarriela has also taught law at the University of the Philippines and at the Pamantasanng Maynila University (PLM). He served as Dean of the Graduate school of Law of PLM. He continues to practice law and serves as the Managing Partner of the Tarriela Tagao &Ona law firm located in Metro Manila.