A highly touted prospect coming out of high school, the 6'4" point guard originally chose to attend the University of Florida, his hometown college. However, after a couple of years Greene became dissatisfied with his playing time and decided to transfer to the University of Louisiana at Lafayette where he became known in the Sun Belt Conference for his aggressive play, winning the Defensive Player of the Year award his senior season. However, in 2007, an NCAA investigation found that Greene had relied on 15 hours of correspondence courses taken through another institution in order to remain eligible for the 2004 spring semester and the entire 2004-05 academic year. NCAA rules do not allow student-athletes to use correspondence courses taken from another institution to remain eligible. According to the NCAA, this was an "obvious error" that should have been caught right away, but the school's then-compliance coordinator director of academic services and registrar all failed to catch it. When school officials learned about the violations, they vacated every game in which Greene participated—43 games in all, including NCAA tournament appearances in 2004 and 2005—and scrubbed Greene's records from the books. The NCAA accepted Louisiana-Lafayette's penalties and also imposed two years' probation.
Professional career
Greene was drafted in 2005 NBA Draft with the 53rd overall pick by the Boston Celtics. Greene began his pro career as backup to Delonte West. His status as the backup point guard was cemented by a season-ending injury to Dan Dickau and the trade of Marcus Banks to the Minnesota Timberwolves. On March 29, 2006, Greene was suspended by the Boston Celtics for one game after he was charged with driving his sport utility vehicle at more than on a street in suburban Boston. On June 30, 2006, Greene was waived by the Boston Celtics. He was claimed off waivers by the Indiana Pacers, and played for their 2006-2007 team. Greene was used very sparingly in his season with the Pacers. He played in only 41 games, averaging 6.2 minutes per game; quite a drop off compared to playing in all but 2 games the previous year with the Celtics and averaging 15.4 minutes per game. The Pacers brought in Darrell Armstrong and Keith McLeod to compete with Greene for minutes at point guard. With Jamaal Tinsley holding the starting position, Greene fell to fourth on the depth chart, which resulted in very little playing time. Greene signed with the Sacramento Kings on August 30, 2007. He was waived by the Kings November 15, 2007 after playing just 7 games. Greene signed a three-month contract with the Australian National Basketball League's New Zealand Breakers in late November 2007. He was signed to replace Wayne Turner, who was out for the season. In 2010 Greene has been banned for two years for trying to dupe drug testers, backdated to March 12, 2009. He later played for the Utah Flash of the NBA Development League. On February 1, 2011 Greene re-joined the NBA as he signed a 10-day contract with the New Jersey Nets. Afterwards, he rejoined the Flash. On November 10, 2011 Orien Greene signed to play basketball for the Halifax Rainmen of the NBL. Shortly afterwards, he joined the Los Angeles D-Fenders of the NBA D-League. In October 2012, Greene signed with the Milwaukee Bucks. He was waived by the team later that month. Later that month, he was re-acquired by the Los Angeles D-Fenders. On February 25, 2013, Greene was traded to the Reno Bighorns. In October 2013, he joined Al Alhy Benghazi of Libya. In December 2014, he joined Fuerza Regia of the Mexican Liga Nacional de Baloncesto Profesional. On December 31, 2016, Greene signed with Guaros de Lara of the Liga Profesional de Baloncesto.
