Mathieu, a Heisman Trophy finalist, and Claiborne were joined on the All-America team by Heisman Trophy winner Robert Griffin III of Baylor and finalists Montee Ball of Wisconsin and Trent Richardson of Alabama.
Heisman runner-up Andrew Luck from Stanford was the second-team quarterback.
The team released Wednesday was selected by a panel of 16 AP poll voters.
The second-ranked Crimson Tide had the most first-teamers with four. Richardson was joined by tackle Barrett Jones, linebacker Dont'a Hightower and safety Mark Barron. Tide linebackers Courtney Upshaw and corner Dre Kirkpatrick also made the second team, giving Alabama the most players selected overall.
The top-ranked Tigers will play SEC West rival Alabama on Jan. 9 in New Orleans for the BCS title.
Since the AP began selecting both an offensive and defensive team in 1964, no team has put a pair of cornerbacks on the first team.
Few teams have had two cornerbacks as talented of Mathieu and Claiborne.
Mathieu, also known as Honey Badger, has been a mayhem-maker for LSU on defense and special teams. He forced five fumbles, intercepted two passes and scored four touchdowns — two on punt returns, two on fumble returns. The 5-foot-9, 180-pound sophomore also had 71 tackles and was versatile enough to be moved around the defense at times.
Claiborne is a prototypical shutdown corner. The 6-1 junior made six interceptions and averaged 29 yards per return, with a touchdown.
"We have one of the best defenses in the country," Mathieu said. "We've got a lot of NFL talent in our secondary, and our defense as a whole."
The talented tandem was a major reason why LSU (13-0) heads to the BCS national championship game against Alabama with a pass defense ranked third in opponents' efficiency, ninth in yards allowed per game and second in fewest touchdown passes allowed.
No. 3 Oklahoma State also had five selections on the three teams, including wide receiver Justin Blackmon, who is one of two players to be selected to the first team for the second straight season.
Blackmon caught 113 passes for 1,336 yards and 15 touchdowns.
Boston College linebacker Luke Kuechly, the nation's leading tackler at 15.9 per game, is the other two-time All-American on this year's team.
Griffin, who is second in the nation in total offense at 396 yards per game, won the Heisman on Saturday, beating out preseason favorite Andrew Luck of Stanford, and the All-America voting went much the same way.
Luck, the Heisman runner-up for the second consecutive year, was a second-team All-American for the second straight year.
Richardson was third in the Heisman voting and Ball, who is one touchdown away from tying Barry Sanders' single-season record of 39, was fourth.
Mathieu finished fifth in the Heisman voting and USC quarterback Matt Barkley, a third-team All-America, was sixth.
Barkley's favorite target, sophomore receiver Robert Woods, was a first-team AP All-America selection. USC tackle Matt Kalil also made the first team.
Clemson also had two players on the first-team, with tight end Dwayne Allen and freshman Sammy Watkins, selected as an all-purpose player.
Watkins and Wing were the only freshman picked to any of the three teams.
The rest of the first-team line had Stanford's David DeCastro and Wisconsin's Kevin Zeitler at guard and Michigan's David Molk at center.
Groza Award winner Randy Bullock of Texas A&M was the All-American kicker.
On defense, three Big Ten defensive linemen made the All-America team: 300-pound tackles Devon Still from Penn State and Jerel Worthy from Michigan State, along with Illinois end Mercilus Whitney, who leads the nation with 14 1-2 sacks.
South Carolina's Melvin Ingram was the other defensive end. Georgia had two defensive All-Americans in safety Baccari Rambo and linebacker Jarvis Jones.
Seven of the 11 All-America defensive players were from the Southeastern Conference, befitting its reputation as the best league in the nation.