Davis attended Sam Houston State University, where he finished his career ranked fourth on the school's tackle list with 339. As a junior, he was named Southland ConferenceDefensive Player of the Year and team MVP after posting 99 tackles and two interceptions. As a senior, he led the team with 96 tackles, seven pass defended, three forced fumbles, one sack, and one fumble recovery. He earned Division I-AAAll-American honors and All-Southland Conference honors after the season. In 2013, he was named to the Southland Conference 2000s All-Decade Team. In 2014, he was inducted into the Sam Houston State Athletic Hall of Honor. On December 7, 2018, Davis graduated from Sam Houston State with a Bachelor of Science in Kinesiology degree.
Davis was signed by the Dallas Cowboys as an undrafted free agent for the 2002 season. He made the Cowboys' practice squad initially, and subsequently the active roster, playing eight games as a backup safety and on special teams. He was credited with five tackles from scrimmage, two quarterback pressures, one pass breakup and eight tackles on special teams. Before the start of the 2003training camp, he was shot in the right hip and left elbow around 2:20 a.m. outside the Dallas Gentlemen's Club. Davis had driven to the club after closing time to pick up a friend. The friend was sitting at a table where an altercation broke out, and spilled outside to the parking lot, culminating with his shooting while defending her girlfriend. While he did nothing to provoke the incident, and was regarded as an unwitting victim, head coachBill Parcells believed Davis should not have placed himself in a questionable situation and released him from the team. Davis did not play football that season, but rejoined the club in 2004, after Parcells gave him a second chance, re-signing him to play in NFL Europe. Davis took advantage of the opportunity and was named All-league, while helping the Berlin Thunder to the World Bowl XII championship. During that season he recorded a team-high 21 tackles on special teams. In 2005 NFL season, Davis started 15 games at free safety and finished fourth on the team with 68 tackles. He also led the club in special teams tackles, with 16, and had a forced fumble. The New Orleans Saints signed him to a restricted free agent offer sheet after the season, but the Cowboys retained him by matching the offer. In 2006, he was shot for the second time in just three years. This time he was randomly shot in the back of the head and in his right thigh, while driving to church at 5:30 a.m. on a Dallas freeway. He drove himself to the hospital and was later discharged. Davis became an unrestricted free agent after the 2007 season. He was third in Cowboys history with 97 special teams tackles.
Davis signed with the Miami Dolphins, reuniting him with team vice president Bill Parcells. In a surprise move, the Dolphins released him a day before the final preseason game.
Dallas Cowboys (second stint)
Just days after being released by the Dolphins, Davis was re-signed by the Dallas Cowboys on August 31, 2008. He was named team captain for the season despite being on the roster only a few days. He also led the team in special teams tackles with 20 and received the Ed Block Courage Award for playing with a torn pectoral muscle.
