O'Brien started his career at the age of six, after being cast in his first feature film role in the independent film "Special Delivery" starring Sean Young, Penny Marshall, and Nell Carter. He followed that up with co-starring roles in Disney's "Smart House," and Hallmark's "A Season For Miracles" with Laura Dern and Lynne Redgrave. He also appeared in a duet entitled "Younger Generation" with singer and good friend Joey Pearson on his album, Something To Say in 2002.

O'Brien currently resides in the Los Angeles area with his parents. After studying Hebrew for six years, O'Brien, who is Jewish, had his Bar Mitzvah in January, 2005.[3] He Finished 7th, 8th and 9th grades in 2 school years and will graduate High School at age sixteen, having skipped the 1st and 4th grades.

Currently dating singer Asha Weisman.

O'Brien is Jewish (of Russian and Austrian ancestry) on his mother's side, and also has Irish, Filipino, Portuguese, Spanish, Armenian, and Japanese ancestry.[1][2]