She is known for playing dramatic roles in film and television. She rose to prominence after winning the reality talent competition StarStruck in Mercado garnered acclaim at a young age for her acting performances on television and film. Mercado's success in Philippine cinema has made her one of the top actresses in the country and established her status as the "Asia's Ultimate Star".
As a child, Mercado suffered physical abuse from her estranged stepfather, Noli Pineda. Her biological mother, Jinkee Pineda returned from Dubai merely to bail her stepfather out. Mercado started as a recording artist with Alpha Records in through the recommendation of her voice coach, Susanna Pichay. Mercado was in Nonoy Tan's singing group, G4.
The group recorded two songs but never released an album due to two of the four members dropping out. In , Mercado joined the reality show StarStruck. After winning StarStruck , Mercado and Herras were launched as a love team in Forever in My Heart , and months earlier they were in the last batch of the teen series Click.
Mercado released her first album Living the Dream , which contained original compositions by Vehnee Saturno, and a carrier single titled "Kahit Sandali". Mercado's first major concert was held at the Music Museum in Greenhills on May 15, Jennylyn Mercado. Mercado starred in Filipino period piece Rosario Mercado's singing career was managed by Viva Records. In , Mercado signed with PolyEast Records to reinvent herself as singer.
In , Mercado acted in the romance The Bride and the Lover In , she played the role of a woman with a split personality through Rhodora X. According to Mercado, this was the most challenging role she has ever played. In late , she released her fifth album through GMA Records. At the end of , Mercado starred in English Only, Please , a role that was originally offered to singer-actress Angeline Quinto.
