The San Francisco 49ers selected him with the seventh overall pick in the 2001 NFL draft, and he also played for the Washington Redskins, New England Patriots and Oakland Raiders.

[1] As a senior, he was a USA Today All-America high school selection, and the Gatorade California Player of the Year.

He was also rated as the top defensive lineman and a high school All-America selection by Parade magazine.

As a senior in 2000, he won the Morris Trophy, awarded to the Pac-10's top defensive lineman, and was recognized as a unanimous All-American.

[5] In the 2005 NFL season, because the 49ers implemented a 3-4 defense under Head Coach Mike Nolan, Carter was moved to outside linebacker.

Carter signed a six-year, $30 million contract with the Washington Redskins as an unrestricted free agent on March 14, 2006.

On Sunday, December 18, 2011, while playing against the Denver Broncos, Carter tore his left quadriceps tendon and missed the remainder of the 2011 regular season as well as the playoffs, as he underwent surgery.

On February 2, 2024, Carter was hired as a pass rush specialist under new Raiders head coach Antonio Pierce and general manager Tom Telesco.