O'Neil was the Director of Participation Accounting with 20th Century Fox Film Corporation in Los Angeles, California. Previously, she was an internal auditor with Metromedia, Inc. in New York before transferring to Metromedia Producers Corporation in Hollywood. She started her accounting career with the CPA firm, Joaquin Cunanan & Company (PriceWaterhouseCoopers, LLP) in Manila. She is a Certified Public Accountant in the Philippines and the State of California. She is a member of the American Institute of Certified Public Accountants (AICPA). Currently, she devotes most of her time giving back to her community by being involved in various civic and service organizations such as the Rotary Club where she is presently the secretary of the Granada Hills Chapter. She also donates her time and resources to various humanitarian organizations doing projects in the Philippines.