Carter made his professional debut in 1996–97, splitting his time with the Capitals and their American Hockey League (AHL) affiliate, the Portland Pirates, before being traded to the Boston Bruins on March 1, 1997. As part of a blockbuster deal, Carter was sent with Jason Allison, Jim Carey, a conditional pick in the 1998 draft and a third-round pick in the 1997 draft to the Bruins in exchange for Adam Oates, Bill Ranford and Rick Tocchet.