A dramatic as well as comedic actor, Ong guest starred in numerous hit television series including Cold Case, ER, Friends, The Suite Life of Zack & Cody, The Bernie Mac Show, Still Standing, Dharma & Greg, Touched by an Angel, V.I.P., Chicago Hope, The Simpsons, and Beverly Hills, 90210.

Ong has also been featured in multiple films including Next (2007), Akeelah and the Bee (2005), Art School Confidential (2005), National Lampoon's Gold Diggers (2004), Leprechaun in the Hood (2000), Godzilla 2000 (1999), The Iron Triangle (1989), and Mac and Me (1988).

On stage, Ong appeared in the hit production of Stephen Sondheim's Tony Award-winning musical, Follies, at East West Players, America's first and foremost Asian American theatre company.

His missionary work extended to AIDS patients in Hollywood, CA, as well as short-term tours in Taiwan, Hong Kong, New Zealand, Sri Lanka, Thailand and Cambodia.

Ong also served on the advisory council of Born to Act Players, a unique organization formed by actor Mary Rings, dedicated to providing a supportive environment for students with special needs to learn and grow by expressing themselves through the performing arts.