Born on February 14, 1985 to parents Reynaldo (a restaurant magnate) and Cecilia Ongpauco, Heart is the youngest in her family, with one brother (Miguel) and four sisters (Lissa, Marjorie, Michelle and Camille).

She was first discovered by a commercial agent while shopping at a mall with sister Camille. She signed up with Star Magic (formerly known as Talent Center) and was paired with John Prats on the show G-Mik. Her relationship with John Prats gained tremendous popularity, and they starred in several movies together—Trip, Ang Tanging Ina and My First Romance. They also starred on another teen-oriented show Berks. After which their real and reel life romance fizzled.

Since then, she was paired with Geoff Eigenmann on the primetime soap opera Hiram which also starred Kris Aquino, Dina Bonnevie, John Estrada and Anne Curtis. This TV show earned her a Star Awards Best Actress nomination at the age of 20.