After being redshirted as a freshman in 2009, Pachall spent 2010 as Andy Dalton's backup. He appeared in eight games and attempted nine passes with six completions for 78 yards and a touchdown. He also ran for 94 yards on 15 attempts with two touchdowns.
In 2011, Pachall took over as the starting quarterback.[3] After seven games, Pachall had completed 131 of 188 passes for 1,566 yards and 17 touchdowns.[4] At that point, his quarterback rating of 165.2 ranked ninth among all NCAA FBS quarterbacks.[5]
He was arrested on Thursday, October 4, 2012, and charged with DWI. At the time, he was suspended indefinitely; playing without Pachall that Saturday, TCU lost its first game of the season, 37–23, to Iowa State. On October 9, TCU announced that Pachall would withdraw from TCU to enter an inpatient rehab facility for substance abuse treatment.[6][7]
Pachall was named TCU's starting quarterback for 2013. He started their opening game against LSU. By the close of his Horned Frog career he held impressive all-time rankings. After 24 games he led in completion percentage (62.9) and ranked third in passing yards (5,415), completions (431), and touchdown passes (42).[8]
Pachall entered the 2014 NFL draft but was not selected. On May 16, 2014, Pachall was signed as a free agent by the Toronto Argonauts of the Canadian Football League.[8] He made the final cut and was on the roster but did not see any playing time. He was listed as inactive through the first 10 games and was released by Toronto on September 6, 2014.[9] He was signed to the Calgary Stampeders practice roster on September 17, 2014.[10] He was released on October 13, 2014.[11]
Pachall was on the developmental league Fall Experimental Football League's Hudson Valley Fort team as starting quarterback at the beginning of the 2015 season.[12] He participated in The Spring League Showcase game on July 15, 2017, on the East team. He completed 4-for-6 passes for 84 yards and a 67-yard touchdown.[13]
