Jameson played collegiately for the Texas A&M Aggies football team from 1997–2000. During his time with Texas A&M, he played all three positions in the secondary: cornerback, free safety and strong safety. He intercepted seven passes during his career, returning three for a touchdown. He also recorded 190 tackles. In 1999, as a junior, he was named second–team All–Big 12 Conference.[1]
The Cleveland Browns selected him in the sixth round of the 2001 NFL Draft and on May 25, they signed him to a three–year contract.[2][3] After being drafted by the Browns, Jameson said about his playing style, "I try to strike first, right at the point of attack. I like to try and use quickness, instincts and athletic ability to deliver the first blow."[4] In the Browns' final preseason game against the Washington Redskins, Jameson broke his leg. He was placed on injured reserve on August 28.[5] The following season, during final cuts, he was waived from the team, only to be re-signed to the practice squad the next day.[6] However, on October 10, he was signed to the active roster.[7] He made his NFL debut on October 13 against the Tampa Bay Buccaneers, recording one tackle in the game.[8] The following week, against the Houston Texans, he received more playing time than he had in his debut.[9] He tallied five tackles and one sack in the game,[8] earning a game ball for his performance.[10] On November 3, he recorded a season–high six tackles against the Pittsburgh Steelers and on December 22, he intercepted his first pass in the NFL.[8] After the season, he became an exclusive-rights free agent and eventually re-signed a $300,000 contract with Cleveland.[11] During training camp, after Robert Griffith broke his finger, Jameson was listed as one of the Browns' two starting safeties.[12] However, Griffith returned before the season began.[13] In 2003, Jameson played in 15 games for the Browns, recording 14 tackles.[14] His season–high in tackles came in week 15 of the season against the Denver Broncos.[15] Jameson, in 2004, played in all 16 games and recorded a career–high 17 tackles.[14] In week 16, against Miami, he recorded four tackles, while the following week, against the Houston Texans, he tallied five tackles.[16] Entering the 2005 season, he was the final member of the Browns' 2001 draft class that still remained on the roster.[17] However, on September 3, he was suspended for four games for violating the league's substance–abuse policy.[18] On October 14, after his suspension was lifted, he returned to practice with the Browns.[19] The Browns terminated his contract on October 17.[20]