Blessed Sacrament-St. Gabriel High School, located in New Rochelle, New York, is where Dennis played his junior year along with cousin Jarrid Famous.
His senior year he averaged 18.2 points per game and won the CHSAA B City Championship against Regis High School in Iona College Gymnasium.
In The Glen Falls Federation championship, Blessed Sacrament won the first game vs Lackawanna High School but came up short against Global Studies.
He joined a potent class of future NCAA Division I standouts in Kentucky's DeAndre Liggins, Florida State's Deividas Dulkys, UTEP's Jacques Streeter, California's Jorge Gutierrez, Seattle's Clarence Trent and UNLV's Carlos Lopez and Brice Massamba.
This class consisted of Phillip McDonald, Nate Garth, Will Brown, Isaiah Rusher, Curtis Dennis, and AJ Hardeman.
The Lobos won the Mountain West Conference regular season championship and earned an automatic bid into the NCAA tournament.
Due to NCAA sanctions and the rule of allowing seniors not to be held accountable, Dennis was able to transfer to Iona College in the Metro Atlantic Athletic Conference (MAAC).
After losing two big players Scott Machado and Mike Glover from Iona's 2012 season it was clear they needed to add a few pieces to relive that run.
Head coach Tim Cluess felt Dennis would be a good piece to that equation in joining Lamont Jones and Sean Armand.
In January 2014 Curtis Dennis signed to a Lebanon Basketball Team Tadamon Zouk with cousin Jarrid Famous.