New York Jets (first stint)
Smith was in attendance for the first round of the draft as many analysts and scouts expected him to be taken that night. However, Smith was not selected, and EJ Manuel was the lone quarterback taken in the first round. Smith declined to be interviewed by ESPN afterwards and originally planned to return home but later decided to attend the second day of the draft. Several league executives alleged Smith did not handle the draft process in a professional manner, which caused him to fall out of the first round, while analysts pointed to his late-season decline as a senior at West Virginia, which exposed his flaws, as the primary reason. The following day, the Jets expressed interest in trading up in the second round to select Smith but could not consummate a trade. Despite this, Smith remained available and the Jets selected him with the 39th overall pick. Following the selection, General manager John Idzik stated that Smith would compete with incumbent Mark Sanchez in training camp to determine the starting quarterback.
Smith fired his agency, Select Sports Group, upon the completion of the draft and sought new representation. He signed with Roc Nation Sports on May 22, 2013, with Kimberley Miale serving as his representative. Smith worked out in his home state of Florida during the offseason, prompting questions as to whether or not he had spurned Sanchez by not attending Sanchez's Jets West summer camp in California. Smith and Sanchez dismissed this notion with Sanchez saying that it was "no big deal."
On July 22, 2013, Smith signed a four-year, $5 million contract with approximately $690,000 in workout bonuses.
Smith made his professional debut on August 9, 2013, in the first preseason game against the Detroit Lions. He completed 6-of-7 passes for 47 yards but left the game due to an ankle injury in the second quarter. X-rays showed no structural damage and Smith returned to practice on August 11. Smith started the Jets' third preseason game against the New York Giants completing 16 of 30 passes for 199 yards, a touchdown, and three interceptions. Smith was named the team's starting quarterback after Sanchez suffered a shoulder injury against the Giants.
During the season-opening 18–17 victory over the Tampa Bay Buccaneers, Smith completed 24-of-38 passes for 256 yards, a touchdown, and an interception. With only a few seconds left in the fourth quarter, he was hit out of bounds by Lavonte David, which drew a late hit penalty and the Jets went on to score the game-winning field goal. In the next game against the New England Patriots, Smith struggled as he completed 15 of his 35 passes for 214 yards, a touchdown, and three interceptions as the Jets lost on the road by a score of 13–10. The following week against the Bills, Smith completed 16 of 29 passes for 331 yards, rushing for a touchdown and passing for two touchdowns and two interceptions. Despite 20 penalties, the Jets powered through and won 27–20. Smith became the first rookie quarterback in franchise history to throw for 300 or more yards in a game.
Smith struggled in the Week 4 38–13 road loss to the Tennessee Titans. He completed 23 of his 34 passes for 289 yards and a touchdown while committing four turnovers—two led to Titans touchdowns as the Jets lost 13–38. During a narrow Week 5 30–28 road victory over the Atlanta Falcons, Smith completed 16 of 20 passes for 199 yards and three touchdowns. He completed all four of his passes on the Jets' final drive, allowing Nick Folk to kick the game-winning 43-yard field goal. Smith was named American Football Conference Offensive Player of the Week and Pepsi NFL Rookie of the Week for his performance. In the next game against the Pittsburgh Steelers, Smith threw for 201 yards and two interceptions as the Jets lost by a score of 19–6. The following week against the Patriots, he completed 17 of 33 passes for 233 yards and scored two touchdowns as the Jets won by a score of 30–27 in overtime.
Smith struggled during the Week 8 9–49 road loss to the Cincinnati Bengals as he completed 20-of-30 passes for 159 yards and two interceptions that were returned for touchdowns before being relieved of duties by Matt Simms in the fourth quarter. Smith started in the next game against the New Orleans Saints and completed eight of 19 passes for 115 yards to go along with six carries for 18 yards and a touchdown in a 26–20 upset victory. The Jets returned from their bye week to lose three straight contests to the Bills, Baltimore Ravens and Miami Dolphins. Smith struggled during this stretch as he failed to score any points and committed eight turnovers; he was benched in favor of Simms against Buffalo and Miami leading coach Rex Ryan to be noncommittal in starting Smith the rest of the year.
Smith showed gradual improvement as the Jets won three of their final four games. During a Week 14 37–27 victory over the Raiders, Smith completed 16 of his 25 passes for 219 yards, a touchdown, and an interception to go along with five carries for 50 yards, keeping the team in playoff contention. In the next game against the Carolina Panthers, Smith performed well until throwing a costly pick six in the fourth quarter. The Jets lost on the road by a score of 30–20 and were eliminated from playoff contention. Smith finished the game completing 15 of 28 passes for 167 yards, a touchdown, and interception. The following week against the Browns, Smith completing 20-of-36 passes for 214 yards and two touchdowns to go along with 10 carries for 48 yards and a touchdown as the Jets won by a score of 24–13. In the regular-season finale against the Dolphins, Smith completed 17-of-27 passes for 190 yards and a touchdown to go along with 10 carries for 44 yards and a touchdown as the Jets won on the road by a score of 20–7, eliminating Miami from playoff contention.
Smith finished his rookie year with 3,046 yards, 12 touchdowns, and 21 interceptions to go along with 72 carries for 366 yards and six touchdowns in 16 games and starts.
Smith was named the starter to begin the 2014 season. He began the season passing for 221 yards, a touchdown, and an interception in the 19–14 season-opening victory over the Raiders. In the next game against the Green Bay Packers, he passed for 176 yards, a touchdown, and an interception to go along with seven carries for 26 yards and a touchdown in the 31–24 road loss. The following week against the Chicago Bears, Smith's very first play resulted in an interception returned for a touchdown by Ryan Mundy. Smith finished the game with 316 passing yards, a touchdown, and two interceptions as the Jets lost to the Bears by a score of 27–19.
During a Week 4 24–17 loss to the Lions, Smith threw for 209 yards with an interception and lost fumble. On October 3, 2014, he was fined $12,000 for yelling profanity at fans while walking to the locker room during halftime in Week 4. Despite this incident, Smith was allowed to start in the next game against the San Diego Chargers, in which he threw for only 27 yards with an interception and was benched for the second half in favor of Michael Vick as the Jets were shut out on the road 31–0. Prior to the Week 5 game, Smith and a few of his teammates missed a team meeting, having gone to a movie theater in San Diego, unaware of the three-hour time difference between the Eastern and Pacific Time Zones. Smith started in the Week 6 31–17 loss to the Denver Broncos, throwing for 190 yards, two touchdowns, and an interception.
During a 27–25 road loss to the Patriots in Week 7, Smith threw for 226 yards and the Jets combined for 218 rushing yards, but the potential game-winning drive fell short due to a blocked field goal. In the next game, Smith lasted only ten minutes to begin regulation as he completed 2-of-8 passes for five yards and three interceptions against the Bills, and was subsequently benched in favor of Michael Vick. His passer rating for that game was 0.04.
In the regular-season finale against the Dolphins, Smith led the Jets to a 37–24 road victory, completing 20 of 25 passes for a career-high 358 yards, three touchdowns, no interceptions, and a perfect passer rating. This was his first perfect game, the sixth in Jets history, and the only one of the 2014 season.
Smith finished his second professional season with 2,525 passing yards, 13 touchdowns, and 13 interceptions to go along with 59 carries for 238 yards and a touchdown in 14 games and 13 starts.
On August 11, 2015, Smith was involved in an altercation with defensive end IK Enemkpali in the locker room over an alleged $600 unpaid debt. Smith suffered a fractured jaw after Enemkpali punched him in the face. Smith was ruled out for 6–10 weeks, and Enemkpali was released by the Jets shortly thereafter. Two days later, Smith underwent surgery on his fractured jaw. Ryan Fitzpatrick led the team to a 2–0 record while Smith was injured, so new head coach Todd Bowles decided to continue starting Fitzpatrick, even with Smith being healthy.
During a Week 8 34–20 road loss to the Raiders, Smith entered the game in relief of Fitzpatrick, who left the game with an injured thumb. Smith completed 27 of 42 passes for 265 yards, two touchdowns, and an interception to go along with two carries for 34 yards. This was his only appearance in 2015.
With Ryan Fitzpatrick re-signing with the Jets, Smith continued to remain in the backup role.
During a Week 6 28–3 road loss to the Arizona Cardinals, Smith came in after Fitzpatrick was benched for poor performance. Smith finished the game completing four of six passes for 31 yards and an interception. Two days later, he was named starter for the following game in place of Fitzpatrick.
Making the start in Week 7 against the Ravens, Smith threw for 95 yards and a touchdown until leaving the eventual 24–16 victory with an apparent knee injury. The next day, it was revealed that he tore his ACL, prematurely ending his 2016 season. Smith was placed on injured reserve on October 26, 2016.
