Originally from Southern California, Dennis started playing hockey at the age of 4. He began his career playing AAA hockey for the LA Selects, LA Jr Kings, and Anaheim Jr Ducks. Being on a Tier 1 AAA hockey team allowed Dennis to experience many different tournaments such as SilverSticks, Quebec PeeWee Tournament, Bell Capital Classic, and Nationals where he medaled twice. 

After his AAA years, he received the opportunity to attend a prestigious Prep-School,  Kimball Union Academy. During his two years at KUA, Dennis was a multi varsity sport athlete playing hockey, lacrosse, and soccer.  While there, he was fortunate enough to win the New England Prep School Championship in 2010.

After his junior year, Dennis headed to Wichita Falls, TX to play in the NAHL. Shortly after arriving, he was called up to play in the USHL where he spent the next three years. During that time Dennis played for the Cedar Rapids RoughRiders and the Sioux Falls Stampede where he was named assistant captain. In his final year of juniors, Dennis was selected as the Captain of Team USA in the World Junior A Challenge, where he led his team to a gold medal.

Dennis was offered a full scholarship to play collegiate D1 hockey at the University of Massachusetts Amherst. In his freshmen year he led his team in scoring, and received the team award for Rookie of The Year. After his freshman year, Dennis was selected to attend the Anaheim Ducks Development Camp where he scored a hat trick in the final scrimmage. During his sophomore year, he received Hockey East Player of the Month for October, All Tournament Team MVP,  as well as  All California D1 Men's Hockey team.

When the opportunity came for Dennis to start his professional career, he jumped at the chance and attended Calgary Flames Development Camp. From there he was invited to attend the Flames Rookie camp and NHL camp. He finally ended up in New York, playing for the Adirondack Thunder in the ECHL. Following his first year he accepted the opportunity to play for the Fort Wayne Komets in Indiana, where he received the "Mr Hustle" award appointed by his teammates and upper management. His final year pro he decided to return to the Adirondack Thunder. Due to a career ending injury, Dennis turned his attention to coaching, where he could focus on the development of athletes.