[3] Spending the entirety of his career with the Cape Breton Screaming Eagles to date, Ellis was traded to the Shawinigan Cataractes in December 2011,[4] and would help the team capture the 2012 Memorial Cup that following April.

[7] In 2012–13, his first professional season, he was assigned to play in the American Hockey League (AHL) with the Hamilton Bulldogs, skating in 71 games and registering four goals and four assists for eight points, along with 57 penalty minutes.

[10] On February 26, 2016, Ellis was recalled by the Canadiens and played in his first National Hockey League (NHL) game on March 2, 2016,[11] in a 3–2 shootout loss to the Anaheim Ducks at the Honda Center.

Once again a free agent at season's end, Ellis moved to the Deutsche Eishockey Liga (DEL), agreeing to a one-year contract with German outfit Kölner Haie on May 9, 2018.

[17] Ellis continued his journeyman European career in 2019–20, signing a one-year contract with Russian club HC Sochi of the Kontinental Hockey League (KHL) on May 2, 2019.