Toni was born on January 20, 1984, to Methodist parents Carlito and Crisanta Gonzaga. Her birth name, Celestine, was given to her father by a boxer. She has a younger sister named Catherine. She began to sing at the age of four participating in various singing competitions. She took up mass communications at the Dominican College, where she studied for two years. Later, she transferred to the AB English program of the Asian Institute for Distance Education (AIDE). Aside from her career in show business and the music scene, Gonzaga was once a Sunday school teacher and a Barangay Kagawad in Taytay. At 17, she struggled as a lounge singer in several Philippine hotels and bars at night while attending school during the day. Her agent later informed her of an audition for a local TV commercial for Sprite.