Cruz started her career at a very young age. She won the FAMAS Best Child Actress award for her portrayal in the movie "Mga Basang Sisiw" opposite Janice de Belen, Che Che and the late Julie Vega. She also won best child Actress for the movie "Roman Rapido" opposite her late uncle the King of Filipino Movies, Fernando Poe Jr.. She was also in the movie "Ang Leon at Ang Kuting"(1980) with Fernando Poe Jr. and in the movie "Tropang Bulilit"(1981) with Niño Muhlach and Lea Salonga.

Her parents were both Sampaguita Pictures stars - Ricky Belmonte and Rose Marie Sonora. Her ethnicity is French-Chinese on her maternal side, Tagalog on her paternal side, and Spanish-Filipino on both her maternal and paternal sides. She is the niece of Actress Susan Roces, the Queen of Filipino Movies. Cruz and her husband Norman Bustos were married in 1996 but filed for divorce in March 2008. They have a daughter named Ashley Nicole.

Her movie career blossomed as part of Philippine cinema's most memorable loveteams, that of herself and Romnick Sarmenta. Sheryl then signed a contract with Seiko Films. Sheryl was named during her teen years as "The Princess of the Philippine Movies". She later married and moved to the United States. In August 2004, Sheryl decided to return home, and starred in her comeback movie, Mano Po 3: My Love, with her godmother the Star for All Seasons, Ms. Vilma Santos-Recto, governor of Batangas.

But her biggest break was starring in two seasons of Now and Forever, "Tinig" and "Ganti", which garnered high ratings (equivalent to that of a primetime show) despite its being on an afternoon timeslot. She appeared on Bakekang, in which her antagonist character, Valeria, became a household name. In 2007-2008, she transferred to ABS-CBN after her blooming career on GMA when she was offered to play Miss Minchin, the main antagonist of Princess Sarah, as Xandra in Komiks Presents: Varga, and a special participation role in Lobo that is starred by Angel Locsin. She decided to transfer back to GMA Network and decided to stay at her home network to do Luna Mystica, opposite a former talent of ABS-CBN, Heart Evangelista.

In 2011, Cruz moved to TV5 and joined the cast of Mga Nagbabagang Bulaklak.

In 2012, she later returned again to ABS-CBN as Cruz appeared in a special participation role in the last episodes of the hit phenomenal teleserye Walang Hanggan, playing the role of a younger Manang Henya (portrayed by her aunt Ms. Susan Roces) in flashbacks. She, along with her cousin Sunshine Cruz, is currently a part of the 2013 hit afternoon action-horror-drama series Galema: Anak ni Zuma, starring Andi Eigenmann.

On December 7, 2013, Cruz won the P1,000,000 in The Singing Bee with four consecutive answers.

She returned to her home network, GMA Network once again in 2014. She had been working there ever since. She has been given many roles and TV appearances. Her latest role is in the afternoon drama series Buena Familia. She portrays Josephine Carter, alongside Bobby Andrews, who portrays Arthur Buena, her love interest and Angelu de Leon as Bettina Agravante-Buena, whom she sees as her competition for Arthur's love.