2007-08: Cameron Darcy skated for the Dexter School in Massachusetts as an eighth grader. He was the team's third leading scorer with 3 goals and 6 assists in 16 games.
2008-09: Darcy was Dexter's second-leading scorer as a freshman as the much-improved team reached the semifinals of the New England Prep School Division II tournament. Darcy scored 16 goals with 16 assists in 26 games; trailing only senior Robert Lerro (40 points). Darcy scored both goals in Dexter's 4-2 loss to New Hampton in the Division II semifinals.
2009-10: Darcy shared the scoring lead for Dexter with Nick Bligh and Pat Curtis in his sophomore season as all three finished with 56 points. He scored a team-leading 21 goals with 25 assists in 27 games. Dexter reached the NEPSIHA small school championship game; falling 3-2 to Kimball Union in double overtime. Darcy scored three goals in Dexter's 4-0 semifinal win over Hebron. Darcy was invited to USA Hockey's National Team Development Program evaluation camp in March and was selected to join the program for the 2011-12 season. In April he committed to playing college hockey at Northeastern in 2012-13.
2010-11: Darcy appeared in two games for the NTDP's U18 team — spending most of the season with the U17 squad — and played for the USA's silver medal-winning team at the 2011 U17 World Hockey Challenge in Canada. He had no points nor penalties for the U18 team. In 54 regular season games for the NDTP U17 squad he scored 14 goals with 7 assists and 30 penalty minutes. Darcy had 2 assists and 2 penalty minutes in five games at the WHC. He was selected by Cape Breton in the tenth round (165th overall) in the 2011 QMJHL Entry Draft.
2011-12: Darcy returned to Ann Arbor for his second season with the NTDP — skating for the program's U18 team — and was part of the gold medal-winning U18 team at the 2012 World Junior Championship. Darcy scored 5 goals with 6 assists and 16 penalty minutes in 56 regular season games for the NDTP U18 team. He had no points nor penalty minutes in six games at the WJC. Darcy was ranked 134th amongst North American skaters in Central Scouting's final rankings but was not taken in the 2012 NHL Draft.
2012-13: Darcy skated in nine games for Northeastern as a freshman before leaving the Huskies in November to play for the USHL's Muskegon Lumberjacks. He had 2 assists and was +1 with 8 penalty minutes for Northeastern. Darcy scored 12 goals with 19 assists and was -1 with 40 penalty minutes in 45 USHL regular season games. Muskegon finished fourth in the Eastern Conference before being swept by eventual Clark Cup champion Dubuque in a first round series. Darcy scored 1 goal and was an even plus/minus with 4 penalty minutes in the three-game series.
2013-14: Darcy joined the QMJHL's Cape Breton Screaming Eagles rather than heading back to college hockey. An assistant captain, the 19-year-old was Cape Breton's leading scorer during the regular season with 35 goals and 47 assists and was +3 with 51 penalty minutes in 65 games.