Vega was born and raised in Davao City, the son of Garcilaso Vega, a lawyer, and Beatrice Jumalon. He received his primary and secondary education at the Ateneo de Davao and then moved to Quezon City to attend the Ateneo de Manila University. He graduated with a Bachelor of Arts in General Studies in 1975. Vega obtained his Doctor of Medicine in 1979 from the University of the East Ramon Magsaysay Memorial Medical Center. He then passed the Physicians Licensure Exam in 1980 and completed his surgery training back in his hometown of Davao at the Davao Medical Center in 1985. In 1986, Vega passed the Philippine Board of Surgery Examinations.
