Dupuis was drafted 104th overall in the 2003 NHL Entry Draft by the Columbus Blue Jackets from Hull Olympiques of the QMJHL. On July 28, 2005, Dupuis signed a 3-year entry-level contract with the Blue Jackets. After 5 years in the QMJHL, Dupuis made his professional debut in the 2006–07 season with the Syracuse Crunch of the AHL. During the 2007–08 season on January 22, 2008, Dupuis was traded from the Blue Jackets, along with Darcy Campbell, to the Colorado Avalanche for Mark Rycroft. Dupuis was then sent to AHL affiliate, the Lake Erie Monsters, for the remainder of the year. Dupuis received his first recall to the Avalanche in the 2008–09 season on December 11, 2008. He made his NHL debut in a 4-3 loss against the Chicago Blackhawks on December 13, 2008. In the 2009–10 season Dupuis was again assigned to Lake Erie posting 35 points in 68 contests. Philippe played in four games with the Avalanche and notched his first NHL point, an assist, in a 4-1 victory over the Phoenix Coyotes on November 4, 2009. In the 2010–11 season, Dupuis made the Avalanche's opening night roster out of training camp, securing a position as the team's fourth line center. He scored his first NHL goal, which was short handed, on November 6, 2010, against Andrew Raycroft of the Dallas Stars, as part of a 5-0 home win for the Colorado Avalanche. He also had two assists and was named the first star of the game. Dupuis concluded his NHL rookie campaign with 17 points in 74 games. On July 7, 2011, the Toronto Maple Leafs signed Dupuis to a two-way one-year deal. He made the Maple Leafs opening night roster for the 2011–12 season as the team's fourth line center. Whilst playing in limited minutes, Dupuis struggled offensively and after 30 scoreless games was waived by the Maple Leafs on January 2, 2012. Upon clearing, he was assigned to AHL affiliate, the Toronto Marlies for the remainder of the season. Dupuis regained his scoring touch with the Marlies to help reach the Calder Cup finals with 14 points in 17 playoff games. On July 5, 2012, Dupuis was signed as a free agent to a one-year, two-way deal with the Pittsburgh Penguins. Due to the NHL lockout, Dupuis was directly assigned to AHL affiliate, the Wilkes-Barre/Scranton Penguins, for the 2012–13 season. Dupuis had his season blighted by a concussion which limited his effectiveness in producing 11 points in 34 games. Dupuis signed his first professional European contract on a one-year deal with German club, the Hamburg Freezers of the DEL on June 27, 2013. In April 2014, he had his contract renewed for two years. In the 2015–16 season, Dupuis was Hamburg's leading scorer with 17 goals and 18 assists in 52 contests. When his contract was up, he opted moved on to his second German club, the Thomas Sabo Ice Tigers, signing on May 11, 2016. Dupuis played four seasons with the Ice Tigers in Nürnberg, posting 18 points in 28 games before COVID-19 ended in his final professional season in 2019–20.
Coaching career
On May 16, 2020, Dupuis effectively announced his retirement in accepting the Assistant Coaching position of the Quebec Midget AAA program at Collège Esther-Blondin Phénix.
