2010-11: Colin Sullivan played for Avon Old Farms (CT) prep school. In 27 games, he scored 3 goals and added 12 assists for 15 points. Sullivan has committed to Yale University for the 2011-12 season.
2011-12: Sullivan played his senior year of hockey at the Avons Old Farms Prep school. The big defenseman work really hard on and off the ice to improve his strength and overall game. He finished the season, scoring seven goals along with nine assists while taking no penalties. Sullivan was named to the 2012 Boys' Hockey All-New England Team by the NESPAC coaches association.
2012-13: Sullivan skated in 32 of 38 games for defending national champion Boston College as a freshman. He had 1 assist and was -4 with 6 penalty minutes in limited minutes for the Eagles. Boston College finished second in Hockey East and received an at-large bid to the NCAA tournament after a loss to Boston University in the Hockey East semifinals. BC lost to Union, 5-1, in the NCAA East Regional semifinals.
Sullivan is a strong skater with good balance, and excellent physical conditioning. His biggest challenge will be to overcome what some scouts consider to be questionable hockey instincts, and learning to read the play, especially at faster pace.
Sullivan has left the Boston College program to play for the Green Bay Gamblers of the USHL.