McClement will make $1 million during the 2014-15 season.
"Jay is a veteran centreman who is proficient in the faceoff circle," Carolina general manager Ron Francis said in a statement. "He'll also provide elements of consistency and leadership for our club."
The 31-year-old McClement played the past two seasons for the Leafs and had 12 goals and 15 assists during his time in Toronto.
A native of Kingston, Ont., McClement led the Leafs with a faceoff percentage of 53.6 this past year.
I don't know how he does it. I don't know how he gets his body parallel with the player and pulls it through his legs like that. I know he's tried it a couple times in practice and it's never worked, so how he does it in a game, it's incredible.
— Capitals defenseman Mike Green on teammate Alex Ovechkin's highlight-reel goal against the Devils on Saturday