Early career: minor roles on television and in movies (2002–2006) De Castro began her career with
GMA Network, playing a minor role in the soap opera
Ikaw Lang ang Mamahalin. However, after a few months with the company, she transferred to the rival network
ABS-CBN and became a contract artist of
Star Magic. During her time at ABS-CBN, she continued to play both supporting and minor roles, such as in the teen-oriented show
Berks. and
Miss-Pinoy (2005).
Return to GMA Network and breakout roles (2006–2008) After four years with ABS-CBN, de Castro returned to her home network, GMA Network, in 2006. One of her first roles back was as Honey on the
fantasy-adventure series
Fantastikids, where she starred alongside
Marky Cielo,
Jackie Rice, and
Ryza Cenon, as well as former child star
Paolo Contis and former beauty queen
Melanie Marquez. The reception to the show was positive; journalist Paul Daza of
The Philippine Daily Inquirer compared it favorably to its counterpart on ABS-CBN (the fantasy-drama
anthology Komiks) and commented that based on ratings, "it would seem like the new [GMA-7] stars are outshining the more established [ABS-CBN] performers." At this time, she also performed regularly on GMA's regular Sunday variety show,
SOP Rules. In 2007, de Castro appeared in two television series. The first was the afternoon
teen drama Boys Nxt Door, dubbed into Malay on the Malaysian channel
8TV and aired in
South Korea via
KBS2, becoming the first Filipino drama to air in the country. The second was the action-adventure series
Asian Treasures. De Castro played Clara, an expert on history and geography who would use this knowledge to help the main characters find the titular treasures. The film was a finalist at that year's
Cinemalaya Philippine Independent Film Festival, where de Castro received a Golden Screen Awards nomination in the Best Actress category. That same year, she also played a supporting role in the romantic film
Batanes: Sa Dulo ng Walang Hanggan alongside
Iza Calzado,
Taiwanese singer-actor
Ken Chu, and Marky Cielo. as "a lighter version of
Almost Famous" and "a fun, feel-good movie."
Career resurgence (2009–present) After another supporting role in the television adaptation of comic-book writer
Carlo J. Caparas' graphic novel
Gagambino, de Castro once again landed a lead role in another television adaptation of a Filipino film,
Kung Aagawin Mo ang Lahat sa Akin, opposite
Patrick Garcia,
Maxene Magalona,
Jackie Rice, and
JC Tiuseco. In the series, she played Gladys Andrada (a role originated by co-star
Jackie Lou Blanco), the jealous only biological child of Gilbert (played by Nonie Buencamino) and Clara Andrada (played by Blanco). Regarding her portrayal, columnist Jason John Lim commented that while she knew she was breaking out of her comfort zone, "What she didn't know that she would also begin breaking the expectations of everybody." Right after
Kung Aagawin Mo ang Lahat sa Akin, she played another supporting role on an episode of the drama anthology
SRO Cinemaserye, which chronicled the life story of singer
Eva Castillo (portrayed in this episode by
Manilyn Reynes). Shortly after, she landed another role in the Philippine remake of the Korean television series
Stairway to Heaven alongside
Dingdong Dantes,
Rhian Ramos, and
TJ Trinidad. De Castro portrayed Eunice, the counterpart of Han Yoori (played by
Kim Tae-hee). De Castro watched the original series to attempt to get an idea of who her character was as a person in preparation for the role. Critics received her portrayal well; Jerry Donato of
The Philippine Star, in particular, said, "So far, Glaiza has given her Korean counterpart a run for her money." In 2009, de Castro appeared in five films. The first was the independent political thriller
Bente, where she replaced former
StarStruck contestant and fellow GMA actress
Jewel Mische when the latter refused to film a sex scene she considered "beyond [her] moral standards" as directed by Mel Chionglo. The film was released in June 2009 and received mixed reviews, with Rito Asilo of the
Philippine Daily Inquirer citing its thematic substance and Gomez's and Calzado's "insightful performances" while also going on to blast the film's "disparate stories," "incohesive feel and style," and sudden ending "in a convenient anticlimax." The second film was the horror movie
Tarot, released on August 26. The film, directed by Jun Lana and top-billed by
Marian Rivera and
Dennis Trillo, is about a girl who can predict the future using
tarot cards. A third film,
Ang Manghuhula, was released commercially in September (it had been shown at the
Cinemanila International Film Festival the previous year). The film, directed by Paolo Herras, saw de Castro play the daughter of Messina (
Eula Valdez), a seer. The production was received warmly, with Noelani Torre of the
Philippine Daily Inquirer noting its "fascinating subject matter," "colorful cast," and "visual richness and clarity." The fourth film de Castro starred in 2009 was the independently produced
Astig (international title:
Squalor) alongside
Sid Lucero,
Edgar Allan Guzman, Arnold Reyes, and
Dennis Trillo (who also served as director). In
Astig, de Castro played Elgine, a teenager afflicted with a
sexually transmitted disease who eventually becomes the love interest of Trillo's character. Released in July of that year, it was a critical and financial success, topping the box office of that year's Cinemalaya Film Festival with a profit of . Darwin Chiong of GMA News called the film's
cinematography "remarkable" and praised the cast as a whole, saying, "The movie gathers an ensemble of actors that deliver in the acting department, even those in supporting roles like Glaiza de Castro and Malou Crisologo." Her performance in this film earned her a Best Supporting Actress nomination at the 33rd
Gawad Urian Awards. The fifth film was the sixth installment of the
Mano Po franchise, subtitled ''A Mother's Love''. The film, directed by
Joel Lamangan and top-billed by Sharon Cuneta,
Zsa Zsa Padilla,
Heart Evangelista, and Dennis Trillo, saw de Castro play the younger version of Cuneta's character, Melinda Uy. The film was released on December 25 and was an entry to that year's annual Metro Manila Film Festival. Her first project on GMA for 2010 was in another villain role in
Diva, billed as the Philippines' first musical
comedy-drama series. It debuted on GMA Network on March 1, 2010, and ended on July 30, 2010. The show, which also starred
Regine Velasquez,
Mark Anthony Fernandez,
TJ Trinidad, and singer
Jaya, and is partly based on the American movie trilogy
High School Musical and the American television series
Glee, saw de Castro playing the ambitious Tiffany, who is Lady's (
Rufa Mae Quinto) assistant and soon-to-be a villainess to singer-actress Regine Velasquez's heroine Melody. After
Diva, de Castro auditioned for and won the title role on the primetime fantasy series
Grazilda. The show, a sequel to the
Cinderella story, centers on Grazilda, who is, in turn, based on one of Cinderella's wicked stepsisters,
Drizella. The plot revolves around Grazilda's banishment from her home world of Fantasia to the human world, where she suffers a fate similar to Cinderella's. The series, which premiered on September 13, 2010, also stars
Geoff Eigenmann,
Yasmien Kurdi,
Jolina Magdangal, and
Cherie Gil and marks de Castro's first lead role in a primetime series. Before the show's debut, de Castro said she could not believe her success; she had become accustomed to playing villainous roles and expected to do so for the remainder of her career. The show was a critical and commercial success, beating its rival,
1DOL, by five points in the AGB Mega Manila ratings. In light of the show's success, de Castro's manager, Manny Valera, has decided to turn down any further villain roles on behalf of his talent to build her up as a lead star. On October 30, it was announced that de Castro would no longer be cast in the remake of the film
Temptation Island and would instead be the lead star in the 2011 remake of the 1992 film
Aswang, produced by
Regal Films with film director
Topel Lee. However, her lead role instead went to Lovi Poe. De Castro later played Binayaan in the epic drama
Amaya, opposite
Marian Rivera and
Sid Lucero. In the third quarter of the year, she was chosen to play the role of Heidi Fernandez, which was originally intended for
Alessandra de Rossi, in the Philippine adaptation of
Temptation of Wife. In 2015, de Castro played Althea Guevarra in the lesbian series ''
The Rich Man's Daughter'' alongside
Rhian Ramos. after its original hosts left following a change in the production company's management. She remained a co-host of the variety show, later renamed
Tahanang Pinakamasaya!, until its final episode in March 2024. == Music ==