Campbell first attended the United States Military Academy Preparatory School for one year before entering West Point.

He was the starting Strong safety before suffering a season-ending knee injury in a road game against Tulane.

In 2007, Campbell was named to preseason watch list for the Lott Trophy, that is awarded to the nation's defensive player of the year.

He was selected one of team's captains for his senior season, along with Tony Fusco, Jeremy Trimble and Mike Viti.

Due to a newly implemented rule at the U.S. Military Academy that would change the way cadets are selected in the NFL Draft, Campbell was able to pursue a professional football career.

The rule states: Cadets accepted into the program, "will owe two years of active service in the Army, during which time they will be allowed to play their sport in the player-development systems of their respective organizations and be assigned to recruiting stations.

The rule, known as the "Alternative Service Option", or ASO, has since been suspended after undergoing review by the Department of the Army.

[4] The Army dropped the ASO option on July 8, meaning that both players had to serve two years of their active duty commitment before they can petition for early release.

He chose Air Defense Artillery (ADA) as his duty branch, but served on the coaching staff at the Army Prep School.

[7] On April 26, 2008, Campbell, along with punter Owen Tolson, were featured in an interview piece on CNN's Headline News.

The piece featured interviews with both players and Army football head coach Stan Brock.

In addition, the two players discussed the Department of the Army's alternative service option plan which would allow them to play in the NFL in 2008.

The CNN Headline News piece was the second national story about Army players' NFL chances that week.

He was interviewed by the ESPN broadcasters, and asked about his opinion on the "service option" rule that allowed him and teammate Owen Tolson to enter the NFL Draft upon graduation.

While being interviewed, and before teams made their seventh round draft selection, fans could be heard chanting "Ca-leb Camp-bell" or "US...USA" in support of Campbell.

Upon his selection by the Lions, Campbell received a standing ovation by the fans in attendance as well as numerous chants and cheers.

However, he did not have a chance to sign the contract and the following day the Army ordered him to serve his military service time, preventing him from playing football until at least 2010.

[12] Being an unsigned draft pick in 2008, Campbell became an unrestricted free agent in 2009, but was then serving military time.

[16] According to the NFL website, during the 2010 season Campbell participated in three games and had a total of three tackles (two solo & one assist).

His younger brother, Jeremy, has a prosthetic leg, yet still played quarterback on his high school football team.

Jeremy Campbell participated in the Paralympic Games in track in 2006, and remains a member of the U.S. national team.