2009-10: Tommy Hughes appeared in seven OHL games with the London Knights while also skating in two junior A games with the London Nationals and playing for the Junior Knights midget AAA team. He had no points and was -1 in his brief OHL experience. Hughes had no points in two games with the Nationals in the GOJHL. He scored 5 goals with 15 assists in 27 games and had 38 penalty minutes with the Junior Knights. In ten playoff games he scored 3 goals with 5 assists and had 12 penalty minutes.
2010-11:Hughes joined the London Knights at the end of November and played 39 OHL games. He had 6 assists and was +9 with 39 penalty minutes. London was fifth in the Midwest Division and took Memorial Cup-bound Owen Sound to six games in a first-round playoff series. Hughes was -1 with no points and 12 penalty minutes in the series with Owen Sound. Hughes played 24 junior A games with the London Nationals and had 2 goals with 11 assists and 54 penalty minutes.
2011-12: Hughes skated in 56 games for London as a 19-year-old in his first full season with the Knights. He scored 2 goals with 8 assists and was +30 with 64 penalty minutes. London finished first in the Midwest Division and reached the Memorial Cup after capturing the OHL playoff title. Hughes scored 1 goal with 3 assists and was +9 with 20 penalty minutes in 19 playoff games. In four Memorial Cup games he had 1 assist and was +1 with 4 penalty minutes.
2012-13: Hughes attended the New York Rangers tryout camp but was not signed and returned to London for an over-age season. An assistant captain for the Knights, he scored 1 goal with 15 assists and was +17 with 66 penalty minutes in 67 games. The Knights again finished first in the Midwest Division and earned their second straight trip to the Memorial Cup; overcoming a 3 games to 1 deficit against Barrie in the OHL finals. Hughes scored 1 goal with 1 assist and was +8 with 19 penalty minutes in 20 OHL playoff games. He had 1 assist and was -5 with 4 penalty minutes in five Memorial Cup games. Hughes signed a three-year entry-level contract with the Rangers in April 2013.
Hughes signed an entry-level contract with the New York Rangers in April of 2013. He begins his pro career in 2013-14 with the Hartford Wolf Pack of the AHL.