2005-06: Mathieu Perreault had an up-and-down rookie season in his first year with Acadie-Bathurst in the QMJHL. Perreault finished the year strongly, finishing seventh on the Titan in scoring with 18 goals and 34 assists and was +20 with 42 PIM. Perreault was a fixture on the Titan second line and elevated his game drastically in the playoffs. After finishing second to Moncton in the East Conference, Acadie-Bathurst eliminated PEI and Cape Breton before falling to Quebec in a seven game series. In 17 playoff games, Perreault scored 10 goals with 11 assists and was +3 with 8 PIM. He scored five goals on the power play and two short-handed.
2006-07: Perreault flashed his high offensive upside and broke out in his second season with Acadie-Bathurst. While the Titan slipped to the middle of the pack in the Eastern Conference, Perreault and Thomas Beauregard were an explosive offensive combination. Perreault finished second in scoring on the Titan behind Beauregard with 41 goals and 78 assists and was +28 with 66 PIM in 67 games. Perreault scored 13 of his 41 goals on the power play and was named Offensive Player of the Month (November). He was also dangerous as a penalty-killer; scoring 9 shorthanded goals. In the playoffs, Acadie-Bathurst eliminated PEI in a seven-game, first-round series before falling to Cape Breton. Perreault scored 6 goals with 8 assists and was -3 with 8 PIM in 12 playoff games.
2007-08: Perreault made his AHL debut with Hershey in the Calder Cup playoffs and was the QMJHL's leading scorer in his third season with Acadie-Bathurst. Perreault joined the Bears in April following the QMJHL playoffs and made his first playoff appearance in Game 1 of their first round series with Wilkes-Barre/Scranton. In three playoff games he finished with no points and was -2. In 65 games with Acadie-Bathurst, he scored 34 goals with 80 assists and had the third-best plus/minus amongst QMJHL forwards (+33). Perreault was awarded the Jean Beliveau Trophy as the league’s leading scorer and was named Second Team All-QMJHL and Second Team All-CHL. He played for the QMJHL team in the ADT Canada-Russia Challenge and was named QMJHL Offensive Player of the Week twice (11/4 and 2/10). Perreault set a Titan record with a 27-game point-scoring streak (11/28 – 2/15), the longest of the year in the QMJHL. Perreault was honored as the Offensive Player of the Month in March for his stellar play. In the playoffs, the Titan eliminated the St. John's Fog Devils in the first round before falling to the Saint John Sea Dogs. Perreault had an eye-popping 19 assists along with 3 goals in 12 playoff games and was +14 with 6 PIM.
2008-09: Perreault got off to a fast start in his first season of pro hockey; scoring a goal against Wilkes-Barre/Scranton in his first AHL game on October 8 and posting points in the Bears' first four games. Playing on a line with fellow rookies Oskar Osala and Francois Bouchard, he finished with 11 goals and 39 assists and was +16 with 36 PIM in 77 games. Five of his 11 goals came on the power play. In 21 playoff games, he scored 2 goals with 6 assists and was an even plus/minus with 8 PIM. The Bears defeated Manitoba in a six-game final to win the Calder Cup.
2009-10: Perreault got off to a quick start in his first career NHL action and split the season between Washington and AHL Hershey. In his first NHL game Perreault assisted on both Washington goals as the Capitals, playing without Alexander Ovechkin, lost 3-2 to New Jersey on November 4. He scored his first NHL goal two games later in a 7-4 win over Florida on November 7 and remained with the Capitals until mid-December. He returned to the Capitals at the end of the season and scored goals in two of the three games he played. In 21 games with the Capitals, Perreault scored 4 goals with 5 assists and was +4 with 6 PIM. Perreault was at his playmaking-best in the AHL with Hershey – putting up nearly a point per game. He scored 16 goals with 34 assists and was +23 with 34 PIM in 56 games for the Bears with 7 of his 16 goals coming on the power play. In the Calder Cup playoffs, he scored 7 goals with 12 assists and was +14 with 18 PIM as the Bears captured their second consecutive AHL championship.
2010-11: Perreault skated in 35 games for the Capitals in two NHL stints and played for AHL Hershey. He was sent to Hershey after just three games with the Caps; returning to Washington in December and skating with the Caps through February; finishing the season in the AHL. In 35 NHL games, Perreault scored 7 goals with 7 assists and was -3 with 20 PMs. He skated in 34 regular season games with Hershey and scored 11 goals with 24 assists and was +8 with 38 PMs. Perreault played all six games in the Bears' first round series with Charlotte and was Hershey's second leading scorer with 3 goals and 3 assists.
Perreault is a small but quick, shifty skater who is a slick playmaker. He has great vision and a keen awareness of his teammates. He is equally adept at releasing a quick shot or making a tape-to-tape pass to an open teammate to create scoring chances. He is a strong centerman and a very good face-off man despite his diminutive size. He has proven to be a clutch, big-game player who produces constant offensive pressure while taking care of his own end. While his lack of size may always be an issue, there is no questioning Perreault’s talent.
Perreault was dealt to the Anaheim Ducks prior to the start of the 2013-14 season, in a deal that brought AHL forward to the Washington Capitals' organization.