The Charlotte (N.C.) Observer said the one-year deal is worth $1.3 million.
Brown was the first choice of the 2001 draft by the Washington Wizards when Michael Jordan, the current Bobcats owner, was involved with the Wizards' management.
Brown played four seasons with Washington and also was on the Los Angeles Lakers and Memphis Grizzlies before spending the last two seasons with the Detroit Pistons.
Brown, 28, averaged 3.3 points and 3.7 rebounds in 48 games last season. In 510 career NBA games, he's averaged 6.7 points and 5.4 rebounds a game. His best season was 2003-04 when he averaged 10.9 points and 7.4 rebounds a game.
"Kwame is a defensive-minded veteran who will add depth to our front court rotation," said Bobcats General Manager Rod Higgins. "At age 28, he has the size, strength and experience to be a solid contributor for this team."