2010-11: Anthony DeAngelo became the youngest player to skate in the USHL when he made his debut with Cedar Rapids as a 14-year-old — skating in three games before his 15th birthday. Signed by the RoughRiders after competing in the 2010 Liberty Bell Games, he appeared in 28 games with Cedar Rapids before breaking his kneecap in a January game. He scored 1 goal with 14 assists and was +4 with 19 penalty minutes. DeAngelo originally committed to playing college hockey at Boston University but in May 2011 announced he would play for the OHL's Sarnia Sting in 2011-12.
2011-12: Making a successful recovery from his knee injury, DeAngelo participated in USA Hockey's Select 16 Player Development Camp before skating in his first OHL season with Sarnia. One of two players to play all 68 regular season games for the Sting, he scored 6 goals with 17 assists and was -6 with 46 penalty minutes. Sarnia finished second in the West Division and lost to Saginaw in a first round series. DeAngelo had an even plus/minus and scored 1 goal with 2 penalty minutes in six playoff games.
2012-13: DeAngelo played for the USA U18 team in the 2012 Ivan Hlinka Memorial Tournament in August before returning to Sarnia for his second OHL season. He scored 9 goals with 49 assists in 62 regular season games and was -13 with 60 penalty minutes. Sarnia was swept by Plymouth in a first round series after finishing third in the West Division. DeAngelo scored 1 goal with 2 assists and was -5 with 8 penalty minutes in four playoff games. He was the leading scorer amongst defensemen for the USA at the Ivan Hlinka tournament with 6 assists in four games and was +1 with 26 penalty minutes. The USA finished seventh.
2013-14: DeAngelo was invited to USA Hockey's U20 evaluation camp in Lake Placid before returning to Sarnia for his third season with the Sting. DeAngelo was selected to play for the USA at the 2014 World Junior Championship. He played in the 2013 CCM/USA Hockey All-American Prospects Game in September and was named to Team Cherry for the 2014 CHL/NHL Top Prospects Game.