Sia was born in Iloilo City in 1977 and grew up in Roxas City, the eldest of three siblings having parents from both Capiz and Iloilo. He was nicknamed "Injap", a portmanteau of "Intsik" (the Filipino pejorative for a Chinese person) and "Japanese"; as his father, Edgar Sr., is half Chinese, while his mother, the former Pacita Jaruda, is half Japanese.