2008-09: Charles-Olivier Roussel skated for Shawinigan as a 17-year-old and had nearly a point-per-game in the playoffs as the Cataractes reached the QMJHL Finals. In his second season with the Cataractes, he had 11 goals with 33 assists and was plus-31 with 77 penalty minutes in 68 regular season games. The Cataractes finished with the league's second-best record and lost to Drummondville in the championship series. Roussel scored 5 goals (all on the power play) with 13 assists in 21 playoff games and was plus-2 with 14 penalty minutes. Ranked 36th amongst North American skaters in Central Scouting's final rankings, he was selected by Nashville in the second round (42nd overall).
2009-10: Roussel returned to Shawinigan for a third season after attending the Canada U-20 and Nashville camps. He was the fourth-leading scorer amongst all Cataractes skaters; scoring 15 goals with 36 assists and was minus-two with 70 penalty minutes in 64 games. Shawinigan finished third in the Central Division and faced Victoriaville in a first round playoff series. Roussel had 1 assist and was minus-one with 4 penalty minutes in six playoff games. He signed a three-year entry-level contract with the Predators in April 2010.
2010-11: Roussel was obtained from Shawinigan by the Montreal Juniors prior to the season and spent his fourth year in junior hockey with the Juniors. Named an assistant captain, he scored 5 goals with 25 assists in 59 regular season games and was plus-17 with 46 penalty minutes. Montreal finished first in the West Division with the QMJHL's second-best record and reached the second round of the playoffs. Roussel had an even plus/minus in ten playoff games with 1 goal, 3 assists and 10 penalty minutes.
2011-12: Roussel returned to the QMJHL for an over-age season, skating for the powerful Saint John Sea Dogs. The defending QMJHL and Memorial Cup champions, Saint John finished with the QMJHL's best record and again won the league playoff title. Roussel scored 13 goals with 27 assists and was plus-48 with 65 penalty minutes in 58 regular season games. He scored 3 goals with 12 assists and was plus-24 in 17 games as the Sea Dogs lost just once in the playoffs. Roussel scored 1 goal with 3 assists in 4 games at the Memorial Cup as Saint John finished 2-2 after losing to eventual champion Shawinigan in the semifinal game.
2012-13: Roussel appeared in 17 AHL games with Nashville affiliate Milwaukee — spending most of his first pro season with the ECHL's Cincinnati Cyclones. He appeared in one November game with the Admirals and was recalled in December – spending a month in Milwaukee before returning to the Cyclones for the rest of the season. He had 1 assist and was -1 with 15 penalty minutes for Admirals, who finished second in the Midwest Division. Roussel was a key part of the blue line for Cincinnati as the Cyclones finished first in the North Division and reached the ECHL Eastern Conference finals. He scored 6 goals with 11 assists and was +9 with 42 penalty minutes in 40 regular season games and had 1 goal with 4 assists, finishing +6, in 17 playoff games.
Roussel's multi-faceted game attracts attention because he has the ability to fill whatever role is asked of him. Whether it is quarterbacking a power play and threading a pass, or shutting down the opposition's top offensive weapons or even physically intimidating the opposing team, Roussel has the ability to accomplish the task without much difficulty.
Roussel has had to settle into a lesser role with Milwaukee, and has spent time in the ECHL for playing time purposes recently. While a solid player in his own right, he is in a stacked defensive depth chart and will have to make all-around improvements if he wants to be considered for an NHL job ahead of some of his counterparts.