2008-09: Antoine Roussel skated in 58 games for Chicoutimi in his third QMJHL season and represented France in the 2009 U20 Division 1 Group A World Junior Championship. Roussel led the Sagueneens with 110 penalty minutes and also showed some offensive ability; scoring 15 goals with 20 assists in 58 games. He finished the season minus-seven on a Chicoutimi team that reached the playoffs despite winning just 24 of 68 games. The Sagueneens finished third in the East Division and were swept by Rimouski in a first round playoff series. Roussel had 2 assists and was minus-one with 15 penalty minutes in the series with Rimouski. He led third-place France with 6 goals and was plus-five with 2 assists in five games at the WJC 1A tournament.
2009-10: Roussel attended the Blue Jackets rookie camp but did not receive an invitation to main camp before returning to the Sagueneens for his fourth season. Named a team captain prior to the season, he once again led Chicoutimi in penalty minutes but was also the team's third-leading scorer. He was eighth in the QMJHL with 131 penalty minutes while scoring 24 goals with 23 assists in 68 games. Roussel was minus-22 as Chicoutimi once again made the playoffs despite finishing under .500. The Sagueneens again met Rimouski in the first round; taking the Oceanic to seven games in a tightly-contested series. Roussel scored 4 goals with 5 assists and was plus-two with 10 penalty minutes in the series.
2010-11: Roussel attended camp with the Bruins before signing an AHL contract with Boston's AHL affiliate Providence. He appeared in 42 games with Providence and also spent time with the ECHL's Reading Royals during his first pro season. He scored 1 goal with 7 assists and had 88 penalty minutes, finishing plus-five, during the regular season with Providence. The P-Bruins finished fifth in the Atlantic Division; missing the AHL playoffs. Roussel had 1 assist in five regular season games for Reading and was also with the Royals for their playoff run. He had 3 assists and was plus-one with 14 penalty minutes in eight ECHL playoff games.
2011-12: Roussel signed an AHL contract with the Chicago Wolves after impressing in the Canucks' Young Stars camp. Roussel was second to veteran Matt Clackson in penalty minutes for the Wolves, finishing with 177 minutes. He scored 4 goals with 5 assists and was minus-13 in 61 games. Chicago finished first in the Midwest Division but lost to San Antonio in a best-of-five first round series (losing all three games by one goal, twice in overtime). Roussel played in two playoff games and was an even plus/minus with no points and 6 penalty minutes. He represented France at the 2012 IIHF World Championship. In seven games he scored 1 goal with 2 assists and was minus-two with 6 penalty minutes. Roussel signed a two-year entry-level contract with Dallas in July 2012.
Roussel has developed into a full-time NHL forward for the Dallas Stars.