Centomo, a native of Laval, Quebec, Canada, split time last season primarily with Ian Keserich between the posts for the RiverKings. It was Sebastien's second tour of duty in the Mid-South, as he started his CHL time with the Memphis RiverKings in the 2001-02 season.

With Memphis, the 6-foot-1, 195 pound Centomo posted a scintillating 16-1-0 record in 19 games played with one shutout, a 2.09 goals-against-average, and a .934 save percentage. The numbers helped him be selected for the 2002 CHL All-Star Game in Corpus Christi, but he did not play in the classic.

On his return to the Mississippi RiverKings last season, Centomo fashioned an 18-9-3 mark in 33 games, posting three shutouts, a 2.51 goals-against-average, and a .915 save percentage. His numbers for appearances, wins, and GAA led the RiverKings in the respective categories.

Centomo's career highlights with the RiverKings include being fourth on the all-time stat sheet in goaltender wins with 34, second all-time for career shutouts by a net minder with four, and is tied with Scott Brower for the most shutouts in one season by a Memphis/Mississippi goalie with three. Sebastien also recorded the lowest goals-against-average by a goaltender in one season at 2.09 and has the highest save percentage by a goaltender in one season at .934. Both marks were achieved in the 2001-02 campaign in Memphis.

Centomo's background also includes one game in the National Hockey League with the Toronto Maple Leafs during the 2001-02 season, action in the American Hockey League with St. John's and Manitoba, ECHL time with Greensboro, Las Vegas, and Long Beach, and CHL experience in Oklahoma City from 2005 to 2007. He also played one season in Finland, before returning in 2006 to the CHL with the Blazers.