Born on Feb. 17, 1974 in New York, NY, O’Connell was raised by his father, Michael, an art director for an advertising agency, and his mother, Linda, a teacher. From the time he was six, O’Connell was on the path to becoming a performer, taking classes for acting, dance, gymnastics, piano and even fencing. Even at such a young age, he knew that he wanted to be in entertainment. After getting an agent when he was 10, the chunky-faced O’Connell landed a television commercial for Duncan Hines cookies. Following his stage debut in an off-Broadway production of “Water Music,” he auditioned for what turned out to be his breakthrough role, playing the chubby, winsome Vern Tessio in Rob Reiner's classic coming-of-age drama, "Stand By Me" (1986). Set in 1959, the story followed four best friends (River Phoenix, Wil Wheaton, Corey Feldman, and O’Connell) who confront their emotional travails while searching for the body of a young boy rumored to have been killed by a train. Though the film was remembered more for Phoenix’s touching performance and the emergence of future star Kiefer Sutherland, O’Connell more than held his own with his often comical crying fits.
Right after he made a name for himself in “Stand By Me,” O’Connell began attending the Professional Children’s School in New York, while continuing to land parts. He made his first made-for-television movie, “The Room Upstairs” (CBS, 1987), which he followed by starring in the Canadian series “My Secret Identity” (Syndicated, 1988-1991). O’Connell played a young teenager who gets zapped by a photon beam that suddenly gives him superpowers that he uses to fight crimes and solve problems in people’s lives. Once the show was off the air, O’Connell matriculated at New York University, where he studied film and television while continuing to work, though he left in 1994 several credits shy of graduation. After starring in the short-lived comedy "Camp Wilder" (ABC, 1992), O'Connell was one of three friends in 1962 who try to live out their life-long ambition of meeting Marilyn Monroe in "Calendar Girl" (1993), starring Jason Priestley. O'Connell's returned to television in "Blue River" (Fox, 1995), based on the novel by Ethan Canin, showcased his now pumped-up physique, as well as his ability to play both youthful and middle-age versions of an unstable man coping with a dysfunctional family.
O'Connell achieved his second career highpoint with his next project, starring in the cult sci-fi adventure series, "Sliders," playing a physics grad student who unwittingly creates a doorway to parallel universes. Along with his best friend (Sabrina Lloyd), his professor and mentor (John Rhys-Davies) and a musician (Clevelant Derricks) who happened to be in the wrong place at the wrong time, he slides from wormhole to wormhole leading to parallel universes in hopes of eventually going back home. O’Connell left after four seasons, while the series continued on for one more before closing shop. On the big screen, O’Connell donned "Rambo" gear to battle some pesky cockroaches in "Joe's Apartment" (1996). Based on the popular MTV short of the same name, the film featured a lovelorn protagonist whose life is ruined by his "friendly" insect roommates. He also won the coveted role of a football player handled by sports agent Tom Cruise in "Jerry Maguire" (1996) before tackling the part of Neve Campbell's boyfriend in "Scream 2" (1997).
After playing a reverend in the made-for-television movie “What the Deaf Man Hear” (CBS, 1997), he was one of eight singles whose night of drunken debauchery goes awry after one of the girls (Tara Reid) claims she was raped in “Body Shots” (1999). He appeared in the two-part miniseries “The 60s” (NBC, 1999) and was an astronaut in the sci-fi misfire "Mission to Mars" (2000), before starring in the sex-comedy genre, the unfunny "American Pie"-wannabe, "Tomcats" (2001). Returning to television, he found a comfortable niche playing the recurring role of Det. Woody Hoyt on the NBC crime series "Crossing Jordan" (2001-07) for several seasons. O'Connell returned to the big screen as one of a down-on-their-luck duo of losers who run afoul of both the Mafia and a troublesome marsupial in "Kangaroo Jack" (2003). After being one of many celebrities to jump aboard the poker bandwagon by appearing on “Celebrity Poker Showdown” (Bravo, 2003- ), O’Connell voiced Captain Marvel for an episode of “Justice League Unlimited” (Cartoon Network, 2003-06).
O’Connell had a rare writing credit with “First Daughter” (2004), on which he also served as executive producer. In a surprising turn to romantic comedies, he had a supporting role in “Yours, Mine and Ours” (2005), a remake of the 1968 Lucille Ball-Henry Fonda comedy about two high school sweethearts who reunite after the deaths of their spouses and after marrying, discover their children hate the new arrangement. Though he appeared in fewer features as his career progressed, O’Connell was a frequently seen face on television, logging episodes of “Las Vegas” (NBC, 2003-08), “Ugly Betty” (ABC, 2006- ) and “Samantha Who?” (ABC, 2007- ). He co-starred in the short-lived sitcom “Carpoolers” (ABC, 2007-08), playing a lothario dentist left with nothing but an empty house after being divorced by his wife. In 2008, O’Connell poked fun at Tom Cruise and Scientology with a viral Internet parody that led to another satirizing Hillary Clinton during the presidential primary campaign. Meanwhile, he tried his hand at another sitcom, “Do Not Disturb” (Fox, 2008), but the much-maligned comedy set in a hotel failed to attract an audience and was axed from the schedule after only three episodes. His personal life, however, fared better when he and wife Rebecca Romijn had twins at the end of 2008.