McKenzie attended Riverview High School where he was a first-team All-Hillsborough County selection by the Tampa Tribune and second-team all-county pick by the St. Petersburg Times as a running back.
After sitting out the 2005 season due to NCAA transferring rules, McKenzie earned second-team All-Big 12 Conference after recording 129 tackles, two sacks, four forced fumbles, and an interception in 12 games.
Before the 2007 season, McKenzie transferred to the University of South Florida, receiving a hardship waiver from the NCAA allowing him to play immediately.
[1] In 2007, he earned second-team All-Big East honors after setting a school record and team-leading 121 tackles.
As a senior in 2008, McKenzie once again led the Bulls in tackles with 116 and earned first-team All-Big East honors.
[2] On May 2, 2009, during rookie minicamp, McKenzie tore the ACL in his right knee after getting tangled up with a running back.