O'Neil's life began in Boulder, Colorado, where he attended Dennison Elementary School, marking the early stages of his educational journey. His impressive performance in school oral interpretation classes caught the attention of his family, who subsequently hired an acting coach to nurture his talent. This decision proved to be a wise one, as O'Neil went on to win an impressive five silver and one bronze medal at amateur acting competitions during the summer of 2005. His remarkable skills did not go unnoticed, and he was soon taken under the wing of Cutler Management, who sent him to study acting in earnest.
The next significant milestone in O'Neil's career came when he was cast in The Last Mimzy (2007),which marked his second acting audition. This role not only showcased his impressive acting abilities but also served as a testament to his dedication to his craft.
Outside of his acting pursuits, O'Neil leads a relatively normal life with his family in the foothills outside of Denver, Colorado, near the Rocky Flats Plant. When he's not busy filming or attending school, he enjoys playing video games, with The Lord of the Rings: The Battle for Middle-Earth II (2006) being his favorite title.
As of March 2007, O'Neil is in sixth grade and continues to attend school on set while filming. His family is a close-knit one, with an older brother named Tyler, and they all share a strong Christian upbringing.
