(written from a Production point of view)
O'Hara was born in the Bronx, New York and won 2005 a Taurus World Stunt Award for best work with a vehicle in the film The Bourne Supremacy shared with fellow Star Trek stuntman Darrin Prescott. In 2008 he was part of the stunt team which received a Screen Actors Guild Award for their work on the action sequel The Bourne Ultimatum. Fello Star Trek stuntmen George Colucci, Gilbert Combs, Jeremy Fry, and stunt stunt coordinators Jeff Imada, Darrin Prescott, and Scott Rogers were also part of the team. He has doubled for stars such as Cary Elwes, Dylan Neal, Jim Carrey, Jake Gyllenhaal, Matthew Perry, Hugo Weaving, David Carradine, and Matt Damon.
Among his resume are films such as Batman & Robin (1997), Air Force One (1997), Alien: Resurrection (1997, with Ron Perlman, Leland Orser, Brad Dourif, Raymond Cruz, and stunts by Todd Bryant, Mark Chadwick, Edward Conna, Mark De Alessandro, Dorenda Moore, and Noon Orsatti), Species II (1998), The Rage: Carrie II (1999), Fight Club (1999), The Perfect Storm (2000), Pearl Harbor (2001), American Pie 2 (2001), Windtalkers (2002), Daredevil (2003), The Matrix Reloaded and The Matrix Revolutions (both 2003, with Anthony Zerbe and stunts by Gilbert Combs, Jarrid Eddo, Christian Fletcher, Freddie Hice, Johnny Martin, Jeff Mosley, Tim Rigby, Henry Kingi, Sr., and John Meier), Kill Bill: Vol. 1 & 2 (2003-2004), Spider-Man 2 (2004, with Kirsten Dunst and Donna Murphy), Cursed (2005), Serenity (2005), and Spider-Man 3 (2007, with Kirsten Dunst, James Cromwell, Becky Ann Baker, Robert Curtis Brown, Reynaldo Gallegos, and stunts by Ian Eyre, Denney Pierce, Tim Rigby, Paul Scott, and Paul E. Short).
He has also performed in television series such as Melrose Place, ER, Sliders (starring John Rhys-Davies), Pacific Blue, Buffy the Vampire Slayer, V.I.P., The District, Birds of Prey (starring Dina Meyer and Ian Abercrombie), 24, Medium, and General Hospital.