In 1993, Gilbert became the youngest player to start in the Pro Bowl (22) when he opened for the NFC on the defensive line for the annual NFL All-Star contest.
"We're please to add yet another quality player to our roster, " said Raider Head Coach Bill Callahan. "Sean brings experience and productivity and we look forward to him making a contribution this season.
Gilbert, 33, has played in 140 league games in 10 NFL seasons after entering the league as the third selection overall by the Los Angeles Rams in 1992. He has 42.5 career sacks.
The 6-5, 325-pound Gilbert has not played in 2003. He played five seasons with the Carolina Panthers (1998-2002) after signing as a franchise player. Gilbert led the Carolina defensive linemen in tackles from 1998-2000.
"I'm very excited about joining the Raiders," said Gilbert. "I'm happy to be part of this historic program and I'm looking forward to getting on the field."
The Aliquippa, Pennsylvania native was the third overall pick by the Rams in 1992 after entering the NFL draft following his junior year when he was a consensus All-American. In his second NFL season, Gilbert posted a career-high 10.5 sacks in 1993 to earn Pro Bowl honors.
He spent four seasons with the Rams before being traded to the Washington Redskins, where he posted 107 tackles in 1996.
Gilbert was USA Today's national Defensive Player of the Year while earning Parade All America honors at Aliquippa High School in his hometown.