At Hatboro-Horsham High School, Carroll averaged 26.5 points, 7.3 rebounds and four assists per game as a senior shooting guard.

At the end of high school, Carroll ranked second in scoring in the history of southeastern Pennsylvania, trailing only former Los Angeles Lakers star Kobe Bryant.

That selection teamed Carroll up with players such as the Orlando Magic's Mike Miller, Stanford's Casey Jacobsen and Arizona's Michael Wright to compete in the Dominican Republic in 1998 and Portugal in 1999.

Carroll played in 133 games over his four-year career at the University of Notre Dame and averaged 13.9 points, 4.3 rebounds, 2.4 assists and 0.9 steals.

He appeared in six games for Golden State during the preseason and averaged 2.8 points and 1.0 rebounds before being released prior to the regular season and returned to Roanoke Dazzle.

Carroll signed with the expansion Charlotte Bobcats on February 23, 2005[1] and appeared in 25 games and averaged 9.0 points and 2.4 rebounds in 17.2 minutes.

Bobcats executive vice president of basketball operations Bernie Bickerstaff had the following comments: "Matt was one of our off-season priorities and we are glad to have him back.

[...] He has proven to be the consummate professional on and off the court, and his production has continued to increase since he joined us from the D-League over two years ago.

"[3] On January 16, 2009, Carroll was traded to the Dallas Mavericks along with Ryan Hollins in exchange for DeSagana Diop.

[4] On July 13, 2010, Carroll was traded back to the Charlotte Bobcats along with Erick Dampier and Eduardo Nájera in exchange for Tyson Chandler and Alexis Ajinça.

In his final game, Carroll played for nearly six minutes, substituting at the very end of the fourth quarter for Ramon Sessions and only recorded 1 assist and 1 foul as a statistic.