Career

A pace bowler, he played in 22 Tests for New Zealand between 2005 and 2009, taking 73 wickets. He played first class cricket for Wellington, the Leicestershire County Cricket Club and the Middlesex County Cricket Club. O'Brien made his debut for the national side in March 2005 following injuries to senior international players, such as Shane Bond, Daryl Tuffey and Chris Martin but has been in and out of the side since to replace injured and retired players.

He made his One Day International debut against the England cricket team, and had a tough debut, with figures of 1/59 in 6 overs. However, between 2007 and 2009 he established himself in the Test side, and to a lesser extent, in the ODI side, particularly in the absence of Shane Bond and he is renowned as an 'into-the-wind' bowler who would often bowl at an end that did not offer favourable bowling conditions—especially at Wellington, a ground renowned for strong winds. He enjoyed much success as a fast bowler for the Black Caps, with great performances against England in the UK, and against the West Indies cricket team at home, where he took his best Test figures of 6/75, in a spell of bowling regarded as one of the best in New Zealand.

These performance have given him the reputation as a wicket-taking bowler, and being the go-to man for Daniel Vettori, the captain. He continued his consistent spells against the Australia cricket team, home and away, and for Wellington. He played at Leicestershire during the 2009 season as their overseas player, impressing by taking 21 first-class wickets at an average of 26.04 in a struggling team, including 9 wickets in a game where he took 6/39 on his birthday.

During New Zealand's tour of England in 2008, he had had similar success, taking 15 wickets at 26.80. Against the Pakistan cricket team at home in December 2009, he has become well known for bowling New Zealand to victory by taking 3 wickets while suffering from a broken thumb. In this same series, he took 6 wickets in the next game, including 4/66, dismissing the likes of Salman Butt, Imran Farhat and Misbah-ul-Haq.

The 2010 season was a frustrating one for O'Brien, he took 23 wickets at an average of 27.30 for Middlesex in division two of the County championship. However, Injury restricted his appearances for Middlesex to just seven championship matches, one CB40 match (in which he took 4–41 in 8 overs)& a single FP Twenty20 match. He retired from cricket in January 2012 due to chronic injury problems.