Gilreath attended high school at Robbinsdale Armstrong in Plymouth, Minnesota after transferring from Minneapolis Washburn in Minneapolis, Minnesota where he played for three years.
As a senior, Gilreath caught 26 passes for 424 yards and four TDs, while rushing 28 times for 504 yards and two TDs, also returned 13 punts for 185 yards and 16 kickoffs for 358 yards and a TD.