Bortles accepted the offer from UCF, which was the first college to offer him a scholarship and was located near his home. He was redshirted as a true freshman in 2010. As a redshirt freshman in 2011, he played in 10 games, completing 75 of 110 passes for 958 yards with six touchdowns and three interceptions. As a sophomore in 2012, he started all 14 games at quarterback. He completed 251 of 399 passes for 3,059 yards with 25 touchdowns and seven interceptions. He also rushed for 285 yards and scored eight touchdowns. He was the MVP of the 2012 Beef 'O' Brady's Bowl after completing 22 of 32 passes for 271 yards with three touchdowns and 79 rushing yards against the Ball State Cardinals.
Through the first 11 games of the season, Bortles had an excellent Week 3 with 4 touchdowns and 0 interceptions for a 128.2 rating; he broke 300 yards passing just once in Week 7 with 330 yards, 1 touchdown and 0 interceptions and a 124.7 rating. Excluding these games, Bortles averaged 185.6 yards per game, no games of either 300+ yards or 100+ rating, and had 7 touchdowns and 8 interceptions in those nine games. Through 12 weeks, out of the 20 eleven-game starters Bortles was 17th in yardage and touchdowns, and 18th in rating. However, he had a 100+ rating in the next three consecutive games, compiling 8 touchdowns and 0 interceptions, and 300+ yards in three of the next four games.
As a starter from the 2012 and 2013 seasons, Bortles had a 22–5 (.815) record for the Knights. As of 2016, his career passer rating of 153.9 is the highest for any UCF quarterback with at least 500 pass attempts, and he was fourth in career completions, yards, and touchdowns behind Daunte Culpepper, Ryan Schneider, and Darin Hinshaw.
After finishing 10–6, the Jaguars made the playoffs as the 3rd seed in the 2017 NFL Playoffs. In the Wild Card round, Bortles defeated the Buffalo Bills 10–3 in his first playoff game. He completed 12 of 23 passes for 87 yards and 1 touchdown, a 1-yard pass to Ben Koyack late in the 3rd quarter. He also had a game-high 88 yards rushing on 10 carries. He joined Michael Vick (2004) as the only quarterbacks with more rushing than passing yards in a postseason game since the 1970 merger, and the 75 net passing yards was the lowest by a winning postseason quarterback since Joe Flacco in the 2009 postseason. Due to his poor passing performance in the Wild Card round, Bortles received heavy criticism from analysts and even other players in the league. When confronted about these criticisms, Bortles stated that he "couldn't care less" and even said, "There’s people who think LeBron James sucks, so if that happens, I’m sure there will always be people who always think I suck.” However, Bortles bounced back in the divisional round, leading the Jaguars to beat the heavily favored Steelers 45-42. Bortles completed 14 of 26 passes for 214 yards and a touchdown to stifle a Steelers comeback. This would be Jacksonville's first AFC Championship game since 1999, but they lost to the New England Patriots 24-20 after spoiling a 20-10 lead in the fourth quarter. Bortles finished the game completing 23 of 36 passes for 293 yards and a touchdown. He finished the playoffs completing 57.6% of his passes for 594 yards, 3 touchdowns, and no interceptions. He also rushed for 121 yards.
Bortles established himself as a dual-threat quarterback in his rookie season by rushing for 20 or more yards seven times in 2014, second only to Russell Wilson of the Seattle Seahawks. However, he also led the NFL and set franchise records in taking 55 sacks for 345 yards lost, and compiled a 3-10 record as a starter.
The Jaguars finished 5-11 in the 2015 season, and Bortles again led the league in sacks taken (51), and also interceptions thrown (19). However, the season was also a success for the second-year quarterback in many ways. Bortles set the Jaguars single-season franchise records for passing touchdowns (35), passing yards, (4,428), pass completions (355), and pass attempts (606). His 90-yard touchdown throw to Allen Robinson in week 16 was the longest in the NFL that year. His passer rating was above 80 in eleven games, and he threw a touchdown pass in the Jaguars' first 15 games of 2015, a franchise record. After throwing no touchdowns in the regular season finale, he shared second place with Eli Manning, Cam Newton, and Carson Palmer, behind only Tom Brady's 36. He was also seventh in the NFL in passing yards with 4,428, behind Drew Brees, Philip Rivers, Brady, Palmer, Matt Ryan, and Manning. He was ranked 56th by his fellow players on the NFL Top 100 Players of 2016.
Bortles compiled a disappointing 3-13 record for the 2016 Jaguars, amid considerable turnover in the organization. During a 9-game losing streak, offensive coordinator Greg Olson was replaced by Nathaniel Hackett in Week 8, and head coach Gus Bradley by Doug Marrone in Week 16. The following week, Bortles caught his first career reception from wide receiver Marqise Lee on a 20-yard trick play that netted a touchdown and led to a Christmas Eve victory over the Tennessee Titans. It was Bortles' only game with a passer rating of over 100 in 2016 (compared to five in 2015). Bortles finished the 2016 season with 3,905 yards passing and a 58.9 completion percentage, 23 touchdown passes, 16 interceptions (4th in the NFL), but just 34 sacks, and five 300+ yard games (7th in the NFL). Following the season, Bortles stated that he had suffered from a Grade 1 right AC joint sprain in Week 8, and suffered from wrist tendinitis in the latter part of the season, which could explain his regression.
Bortles is the son of Rob and Suzy Bortles. Rob was a Wrestler and football player in high school; Suzy played high school softball. Bortles's brother, Colby, is a third baseman with the Ole Miss baseball team, and was drafted in the 22nd round of the 2017 MLB draft by the Detroit Tigers.
On February 24, 2018, Bortles signed a three-year, $54 million contract to stay with the Jaguars through the 2020 season.
