As a senior, he helped his team win the state championship in football, receiving All-state, All-district, All-city and Defensive Player of the year honors.
He also practiced track, where he was a two-time Academic All-district selection as a shot putter.
Missouri was selected by the Baltimore Ravens in the seventh round (231st overall) of the 2001 NFL draft.
On September 12, he was waived to make room for linebacker Shannon Taylor, and was signed to the practice squad the next day.
He collected 27 tackles, 5.5 sacks (second in the league), 4 passes defensed and 3 forced fumbles, helping the team win World Bowl X.
[7] In his 4 seasons with the Philadelphia Soul of the Arena Football League, he registered 72.5 total tackles (10.5 for loss), 18.5 sacks, 15 passes defensed, 15 forced fumbles, 2 blocked kicks, 6 receptions for 38 yards and 2 touchdowns.
[9] Missouri was featured in the first season of HBO's Hard Knocks series as a member of the Baltimore Ravens.