Cousin attended Randallstown High School in Randallstown, Maryland. During his junior season, he averaged 14 points and 7 rebounds per game. He also participated in the Charm City Classic All-Star game. During his senior season, he averaged 11 points, 7 rebounds and 4 blocks per game before sitting out the final two months with an ankle injury. Michigan State, Nebraska, USC and Massachusetts were all interested in Cousin, but he eventually decided to sign with Seton Hall.
College career
In his freshman season at Seton Hall, Cousin played sparingly. In 18 games, he averaged 0.4 points and 1.1 rebounds in 6 minutes per game. In his sophomore season, he helped the Pirates to an 18-12 record and a berth in the NCAA Tournament against Wichita State. In 26 games, he averaged 2.1 points and 3.5 rebounds in 13.1 minutes per game. In 2006, he transferred to the University of Houston. Due to NCAA transfer rules, he was forced to sit out the 2006–07 season. In his redshirted junior season at Houston, he finished third on the team in blocks with 22. In 29 games, he averaged 4.4 points and 4.0 rebounds in 13.8 minutes per game. In his senior season, he had his best year of college basketball. In 33 games, he averaged 10.9 points, 8.4 rebounds and 2.1 blocks in 30 minutes per game.
On September 27, 2010, Cousin signed with the San Antonio Spurs. However, he was later waived by the Spurs on October 22, 2010. On October 30, 2010, he was acquired by the Austin Toros as an affiliate player. On March 9, 2011, he signed a 10-day contract with the Utah Jazz. On March 19, 2011, he returned to the Toros. On April 11, 2011, he signed with the Houston Rockets for the rest of the season and was immediately assigned to the Rio Grande Valley Vipers. On May 1, 2011, he returned to the Rockets following the conclusion of the NBA D-League season. On December 24, 2011, he was waived by the Rockets before the start of the 2011–12 NBA season. He did not appear in a game for the Rockets during his tenure.
2012 off-season
In March 2012, Cousin signed with Guaiqueríes de Margarita of the Liga Profesional de Baloncesto in Venezuela for the 2012 LPB season. However, he left after one game. In July 2012, he joined the NBA D-League Select Team for the 2012 NBA Summer League. In August 2012, he signed with Caneros de La Romana in the Dominican Republic for a short stint.
2012–13 season
In September 2012, Cousin signed with Kyoto Hannaryz of the bj league for the 2012–13 season. In 57 games, he averaged 14.5 points and 9.7 rebounds per game.
2013–14 season
On September 30, 2013, Cousin signed with the San Antonio Spurs. However, he was later waived by the Spurs on October 15, 2013. On November 27, 2013, he signed with Krasny Oktyabr Volgograd of Russia for the rest of the 2013–14 season.
In September 2015, Cousin signed with the Shinshu Brave Warriors for the 2015–16 bj league season. He left the team in January 2016 after appearing in 12 games.
