Shane O'Brien was born August 8, 1983 in Port Hope, Ontario. Drafted by Anaheim eighth round, 205th overall in the 2003 NHL Entry Draft, O'Brien played 190 career OHL games with Kingston and St. Michael's Majors.
A sizeable defenceman, O'Brien spent the early part of his professional career with the Anaheim's AHL Affiliate in Cincinnati and Portland over three seasons. He eventually made his NHL debut with the Ducks' in an October 6, 2006 game against the Los Angeles Kings. He would go on to compete in 62 games with the Ducks before being traded to Tampa Bay on February 24, 2007.
As a member of the Lightning, O'Brien would see action in 18 games with the club and make his playoff debut in the team's series against the New Jersey Devils. He returned to the Lightning the following season, appearing in 77 games and notching 21 points. Despite his increase in games played, the Lightning dealt O'Brien and Michel Ouellet to the Vancouver Canucks for Lukas Krajicek and Juraj Simek.
Just days prior to the 2010-11 season O'Brien was dealt to the Nashville Predators in exchange for Ryan Parent.