Isabel is the youngest of seven children of Filipino father of Chinese descent and a Filipina mother of Spanish descent. Isabel finished her secondary education at Cebu Eastern College and college degree from the University of San Jose-Recoletos (Cebu) with the degree in Information Technology. She started to get the attention of the viewers when she landed a role in the Max's of Manila restaurant commercial. She started her acting career in ABS-CBN in 2004 via It Might Be You (2003) and a Maalaala mo kaya (1991) episode with John Prats and Baron Geisler before moving to GMA Network in 2005 However, it was her similarly named role of Isabel, the leading lady to matinee idol, Richard Gutierrez in Sugo (2005), that launched her to full stardom, her exposure on Sugo (2005) also landed her a role on the GMA Films' summer 2006 offering Moments of Love (2006). Her face graced the covers of glossy magazines, billboards and print ads, and appears regularly on GMA-TV shows. Isabel played her antagonist and villain role Rosita, originally played by award-winning actress Lorna Tolentino, in Sine Novela: Maging akin ka lamang (2008). She then appeared in Gagambino (2008), opposite Dennis Trillo. In 2009, she played Iza Calzado's antagonist in her second Sine Novela, Kaya kong abutin ang langit (2009). Oli also played the much-coveted role of Elaine in the Philippine Version of the Korean 2004 television series, Full House (2009). Isabel Oli is part of the cast for the movie Rosario (2010), an MMFF 2010 entry to be shown on December 25, 2010. On March 3, 2014, Oli returned to ABS-CBN to appear in the special finale participation as Chef Bernadette Cruz in Annaliza.