- Jennylyn Anne Pineda Mercado was born on 15 May 1987 and grew up in Parañaque City.
- Jennylyn Mercado was the First female winner of Starstruck Season 1 (2003) of GMA network.
- She is the niece of television reporter, Abner Mercado. Her cousins are Cherie Mercado (news and radio anchor for News5), Charee Pineda, and Eliza Pineda who both work for the ABS-CBN channel.
- Mercado's life story was featured in the weekly drama anthology Magpakailanman on October 14, 2004. She is now the official spokesperson of the Bata Foundation (Christian Mission Services), a non-government organization.
- In 2008, at age 21, Mercado announced that she was pregnant. Her ex-boyfriend Patrick Garcia distanced himself upon learning of her pregnancy, was announced as the father of her child. On August 16, 2008, she gave birth to her child, a son, via Caesarian section.
- She works with the Philippine women's organization GABRIELA.
- She is also an aspiring triathlete for engaging in sporting activities. She took jujitsu and Muay Thai lessons in her free time. "They built up my muscles. I looked heavy onscreen," Jennylyn recounted. "I realized that I needed cardio exercises to slim down." She discovered running and biking, which soon led her to join duothlon competitions in Alabang and Laguna. She is also a diver to inspire people to be environment friendly.
- Mercado started as a recording artist with Alpha Records in 1999 through the recommendation of her voice coach, Susanna Pichay. She was in Nonoy Tan's singing group, G4. Unfortunately the group never released an album because two of the four members dropped out.
- She released her first album, Living the Dream, containing original compositions by Vehnee Saturno, and a carrier single titled "Kahit Sandali". In May 2006, Mercado released her second album Letting Go which included the single "Sa Aking Panaginip" by Vehnee Saturno. Her first major concert was held on May 15, 2006, at the Music Museum in Greenhills. In January 2010, under VIVA Records, she released her third album, Love Is... Jennylyn Mercado. Due to her popularity, she held a birthday concert at the Music Museum, titled I Am Woman in May 2009. The concert was sold-out.
- Her first films included So Happy Together and the teen-flick Let the Love Begin but her most acclaimed film performance was a Filipino period piece, Rosario.
- In 2015, after Mercado's box office hit English Only, Please with actor Derek Ramsay in 2014, she was awarded as the MMFF 2014 Best Actress for the recently concluded film festival.
- A few months later Mercado finally grabbed her first win for the controversial FHM Philippines' 100 Sexiest Woman after beating Andrea Torres and Ellen Adarna, after Marian Rivera (which excluded on the list along with Rookies Tricia Santos and China Roces) vactates the title. Before she leaves Philippines for New York for PreNup film with Sam Milby, publisher Aeus Reyes and Allan Altera with GMA News reporter Nelson Canlas surpries Mercado and give a plaque. And finally on July 11, Mercado ramps for the two part FHM 100 Sexiest party at the SMX Convention Center, SM Mall of Asia.