Junior Ellerby was drafted 10th overall by the
Florida Panthers in the
2007 NHL entry draft from the
Kamloops Blazers of the
Western Hockey League. During the
2008 World Junior Hockey Championship, Ellerby was invited to try out for the tournament, having played for Canada at the
2007 Superseries against the Russians.
Professional Ellerby scored his first NHL goal on January 25, 2011, against
Henrik Lundqvist of the
New York Rangers. During the
2012–13 season, on February 8, 2013, Ellerby was traded by the Panthers to the
Los Angeles Kings for a fifth-round selection in the 2013 NHL Draft. The Kings re-signed Ellerby to a one-year deal in July 2013, but he was claimed off waivers by the
Winnipeg Jets a month into the
2013–14 season. Ellerby signed a one-year contract with the Jets the following summer for the
2014–15 season. He spent most of the season in the minors. On July 7, 2015, Ellerby signed his first contract abroad, agreeing to a one-year deal with
Barys Astana of the
Kontinental Hockey League. After 42 games with the Kazakh-based club, Ellerby sought a release and immediately signed with Swiss team
HC Fribourg-Gottéron of the
National League A on January 4, 2016, for the remainder of the
2015–16 season. Ellerby also played for Team Canada during Spengler Cup and won the championship scoring one of the goals in the final game. The following season, Ellerby signed for the
2016–17 season with
Finnish Liiga outfit,
Lukko Rauma. Ellerby proved to be a solid addition to Lukko's blueline, contributing steady defensive play to go along with 3 goals and 12 points in 43 games. On July 10, 2017, Ellerby agreed to a one-year deal with top tier Swedish club,
Mora IK of the
Swedish Hockey League (SHL). He contributed with a heavily defensive role, logging the most blocked shots in the SHL and playing big minutes. After one season with a struggling club, he agreed to a one-year deal with German club,
Iserlohn Roosters of the DEL, on September 13, 2018. As a free agent midway into the
2019–20 season, Ellerby continued his professional career signing in the neighbouring Austrian Hockey League with the Dornbirn Bulldogs on November 18, 2019. In the 2020–21 season, Ellerby moved to Hungary to sign for
Erste Liga side
Ferencvárosi TC. In August 2021, Ellerby agreed terms with UK
EIHL side
Sheffield Steelers for the 2021–22 season - following in the footsteps of
Justin Hodgman who also moved to Sheffield from Ferencvarosi earlier in the summer. Ellerby retired from hockey in the summer of 2022. ==International play==