As a sophomore in 2006–07, he averaged 11 points and six rebounds per game as Hopkins made it to the section championship.

[1] In November 2008, Cowels signed a National Letter of Intent to play college basketball for Santa Clara University.

[1][3] In his junior season, Cowels was the only player to start every game as he led the team and tied for No.

[1][3] In his senior season, Cowels became the 31st player in school history to score 1,000 career points on February 16 with a corner three in the second half against Pepperdine.

[1][3] On July 18, 2013, Cowels signed a one-year deal with the Den Helder Kings of the Dutch Basketball League.

On November 1, 2014, Cowels was selected with the final pick in the 2014 NBA Development League Draft by the Reno Bighorns.

[7] In July 2015, Cowels joined the Memphis Grizzlies for the 2015 Orlando Summer League,[8] helping the team win the tournament championship.

On December 17, 2015, Cowels signed with the Halifax Hurricanes of the National Basketball League of Canada.

In July 2018, Cowels signed with the Canterbury Rams as a short-term replacement for Xavier Thames, thus returning to New Zealand for a second stint.