[1] He prepped at Fort Stockton High School where he led the football team to the district championship his senior year.
[4] McIvor arrived in Austin in 1979, as part of a highly touted class of quarterback recruits and was often considered as a player that could be moved to defense.
[5] But blessed with exceptional arm strength, the 6 ft 4 in (1.93 m) McIvor showed promise in the 1979 Baylor game when, as a true freshman, he played in place of Donnie Little and threw for 270 yards and so he remained a quarterback.
[6] A few weeks later, after backup quarterback Jon Aune moved to defensive back, McIvor replaced Little in the TCU game, when Little left with sore ankles, leading the team on an 80-yard touchdown drive and running the offense for most of the second half.
[7] His first career start came the next week against Baylor and McIvor played well, throwing for 270 yards, then a Texas record, and 1 touchdown in leading the team to a 13-0 win.
[1] During the off-season, Little volunteered to move to wide receiver because he felt it would be his best shot at an NFL career,[13] and McIvor became the starting quarterback for the 1981 season.
But Todd Dodge was named the starter during summer practices after McIvor spent a couple of days in the hospital with an infected wrist and elbow.
Later in the fall, a shoulder injury to Dodge in the final preseason scrimmage led to McIvor splitting time with his best friend Rob Moerschell in the first game of the season against Auburn.
But, during the last game of the regular season, against in-state rival Texas A&M, McIvor replaced Moerschell when the #2 Longhorns fell behind 14–0 and played spectacularly.
Texas held onto a small lead until late in the 4th quarter but a muffed punt return gave Georgia the opportunity it needed to score the game-winning touchdown.
Having made an impression with his strong arm and clutch play in the Texas A&M game, McIvor was selected 80th overall by the St. Louis Cardinals in the 1984 NFL draft.