2010-11: Adam Erne joined the USHL's Indiana Ice after committing to playing college hockey at Boston University in 2013-14 in July. In 45 games with the Ice he scored 10 goals with 8 assists and was minus-18 with 49 penalty minutes. Indiana finished third in the Eastern Division and reached the second round in the playoffs. Erne was plus-one with 1 assist in three playoff games. He was selected by Halifax in the second round (22nd overall) of the 2011 QMJHL Entry Draft.
2011-12: Obtained by the Quebec Remparts in a July trade with Halifax, Erne decided to forego college hockey and instead skated in the QMJHL. In his first season with the Remparts he scored 28 goals with 27 assists in 64 games and was plus-six with 32 penalty minutes. The Remparts finished third in the East Division and reached the second round in the playoffs. Erne scored 2 goals with 4 assists and was plus-five with 10 penalty minutes in 11 playoff games.
2012-13: Ernie was the leading scorer for Quebec in his second season after representing the USA at the 2012 Ivan Hlinka U18 Tournament in August. In 68 games with the Remparts he scored 28 goals with 44 assists and was plus-11 with 67 penalty minutes. Quebec finished third in the East Division and reached the second round in the playoffs. Erne scored 5 goals with 5 assists and was plus-one with 19 penalty minutes in 11 playoff games. At the Ivan Hlinka Tournament he scored two goals and was named Player of the Game in the Americans' only win – a 5-3 victory over Slovakia. Erne was ranked 26th amongst North American skaters in Central Scouting's final rankings prior to the 2013 NHL Draft.