Noted for his performances in a range of genres across film and television, he began his career as a child actor debuting in the series Gulong ng Palad.

At the early age of four, Sarmenta began his acting career by portraying Peping, the young kid, in the enduring drama series and groundbreaking telenovela Gulong ng Palad (1977–1983).

He debuted as one of the performers on the variety show That's Entertainment, presented by the late Master Showman German "Kuya Germs" Moreno, just three years after his first TV employment.

His debut acting role was in the movie Pinagbuklod ng Pag-ibig, which also starred Nora Aunor, Vilma Santos, Tirso Cruz III, and Romeo Velasquez.

[1] Sarmenta was coupled with a variety of leading ladies throughout the height of his career, including Jennifer Sevilla, Sheryl Cruz, and Harlene Bautista.