After Dalton was drafted by the Cincinnati Bengals, there was much speculation over whether Dalton or veteran Bruce Gradkowski would start at quarterback. Carson Palmer, the first overall draft pick in the 2003 NFL Draft, demanded to be traded or released, and was traded later in the season to the Oakland Raiders. On June 29, 2011, the Bengals signed Dalton to a four-year, $5.21 million rookie contract with a $2.29 million signing bonus and $4.02 million guaranteed.

Dalton attended Katy High School in Katy, Texas, where he played on the Tigers football team. He split time as a junior in 2004 and then started only one full season at quarterback for Katy High School as a senior in 2005. That year, he led the Tigers to the state finals, where they lost to Southlake Carroll, 34–20. As a senior, he threw for 2,877 yards with 42 touchdowns and 15 interceptions. That year, he was named the Greater Houston Area offensive player of the year by the Houston Chronicle.

Dalton committed to Texas Christian University on October 19, 2005.

Entering the 2007 season, Dalton was in competition with Jackson to be the starting quarterback. Two weeks before the season opener against Baylor, TCU head coach Gary Patterson named Dalton the starter. He was named the 2007 Texas Bowl MVP in TCU’s 20–13 victory over Houston. After going 8–5 as a freshman, he accumulated a record of 34–3 as a starter for the rest of his career at TCU.

In the 2008 season, Dalton led TCU to an 11–2 record, finishing second place in the Mountain West Conference and seventh in the national AP Poll. He was named the 2008 Poinsettia Bowl MVP in the Horned Frogs’ 17–16 win over Boise State.

In the 2009 season, Dalton led the Horned Frogs to a perfect 12–0 regular season, a Mountain West Conference Championship, a #6 ranking in the AP Poll, and a BCS berth. The Horned Frogs lost 17–10 in the Fiesta Bowl to Boise State.

On September 4, 2010, Dalton recorded his thirtieth victory as the Horned Frogs starting quarterback, passing Sammy Baugh as TCU’s all-time wins leader. Against Baylor, Dalton completed 21 of 23 pass attempts (a career-best and single game record 91.3%) for 267 yards and two touchdowns. His team won a second consecutive Mountain West Conference Championship. On January 1, 2011, Dalton, who completed 194 of 293 passes for 2638 yards for 26 touchdowns during his senior season, led his team to a 21–19 victory over #4 Wisconsin in the Rose Bowl in Pasadena, California. His TCU football team finished the season with a perfect 13–0 record and #2 ranking in the AP Poll. Auburn, the only other team with a perfect record, won the BCS National Championship that year.

On April 29, 2011, the Bengals selected Dalton with their second round pick, 35th overall, in the 2011 NFL Draft. Out of the twelve quarterbacks that were chosen in the 2011 NFL Draft, he was the fifth selected.

On August 8, 2011, before their first pre-season game versus the Detroit Lions, Bengals head coach Marvin Lewis released his first depth chart per NFL rules, but noted that it meant little. The depth chart had Dalton listed as the first-string quarterback, followed by Gradkowski.

Dalton’s first NFL regular season start came on September 11, 2011, on the road against the Cleveland Browns. Dalton, in one half of play before leaving the game due to injury, completed 10 of his 15 pass attempts for 81 yards and one touchdown, posting a passer rating of 102.4. The Bengals won the game, 27–17, Dalton’s first divisional AFC North victory as well as first win against the divisional rival Browns. Dalton’s second game on was also on the road, against the Denver Broncos. Despite a 24–22 loss, Dalton led a comeback, completing 19 of 29 pass attempts for 280 yards and 2 touchdowns in the second half alone, and achieving a passer rating of 107.0 for the game. In a 27–17 victory against the Indianapolis Colts on October 16, 2011, Dalton completed 25 of 32 passes for 264 yards and 1 touchdown. In that game, Dalton had a season-high 78.1 completion percentage and 111.5 passer rating.

On November 3, 2011, Dalton was named the NFL Offensive Rookie of the Month for October. Dalton led the Bengals to a 4–0 record with 909 yards passing and 6 touchdowns in the month. Dalton then threw for 217 yards and a season-high 3 touchdowns with no interceptions against the Tennessee Titans in a comeback 24–17 victory on November 6, earning him Pepsi NFL Rookie of the Week honors. On November 27, Dalton passed for 270 yards and a touchdown for a 105.6 passer rating in a comeback 23–20 victory over the Cleveland Browns, again winning Rookie of the Week. This game featured a 51-yard strike from Dalton to A.J. Green with only 1:08 remaining in the fourth quarter, setting up the Bengals’ game-winning field goal. By the end of the season, Dalton had led the Bengals to a 9–7 record and a berth in the NFL playoffs.

On July 9, 2011, Dalton married his longtime girlfriend, Jordan Jones, whom he met at TCU. In July 2014, Dalton’s wife gave birth to the couple’s first son. Their second son was born in March 2017.

On January 7, 2012, the Bengals faced the T. J. Yates-led Houston Texans in the wild-card round of the NFL playoffs. This game marked the first time in NFL playoff history that two rookie quarterbacks started in the same game against each other. Dalton completed over 64 percent of his passes but also had three turnovers as the Texans won the game, 31–10.

In the second game of the season on September 16, 2012, Dalton guided the Bengals to a 34–27 victory at home over the Cleveland Browns. He completed 24 of 31 passes for 318 yards, 3 touchdowns, and an interception, for a 128.2 passer rating. In the following game at the Washington Redskins, Dalton completed 19-of-27 passes for 328 yards, 3 touchdowns, and an interception, for a season-high 132.9 passer rating, in leading the Bengals to a 38–31 win. Furthermore, Dalton lined up as a wide receiver on the first play from scrimmage of the game, acting as a decoy while wildcat quarterback Mohamed Sanu threw a 73-yard touchdown pass to A.J. Green, then again flanked as a receiver while BenJarvus Green-Ellis rushed for a touchdown via a direct snap. The following week at the Jacksonville Jaguars, Dalton threw for 244 yards and had three touchdowns (two passing, one rushing) in leading the Bengals to a 27–10 victory.

On October 14, 2012, Dalton threw for a career-high 381 yards to go with three touchdowns against the Cleveland Browns, but also threw three interceptions as the Bengals fell to the Browns 34–24. This was the second game in what would become a four-game losing streak. Dalton and the Bengals rebounded by defeating the New York Giants in a 31–13 game, in which Dalton completed 21 of 30 passes for 199 yards and a season-high four touchdowns, attaining a 127.6 passer rating and a season-high 94.5 QBR. For his efforts against the Giants, Dalton was named the AFC Offensive Player of the Week for the first time in his career. The following week, the Bengals beat the Kansas City Chiefs 28–6 as Dalton completed 18 of 29 passes for 230 yards and two touchdowns thrown (a 109.8 passer rating) while adding a rushing touchdown.

On November 25, 2012, in a much-hyped game with the Oakland Raiders due to the return of former Bengals quarterback Carson Palmer to Cincinnati, Dalton outperformed Palmer by throwing for 210 yards and three touchdowns, achieving a 109.0 passer rating, and leading the Bengals to a 34–10 victory. In the fourth quarter, an unnecessary roughness penalty by Lamarr Houston on Dalton was one part of a sequence of events leading to the ejections of Andrew Whitworth, Tommy Kelly, and Houston from the game. With his performance, Dalton became one of three players in NFL history with at least 20 touchdown passes in each of his first two seasons, joining Peyton Manning and Dan Marino.

In two of the next three following weeks, Dalton’s mobility proved to be valuable as he scrambled for the go-ahead touchdown runs in victories over the San Diego Chargers and Philadelphia Eagles. On December 23, 2012 against the Pittsburgh Steelers, his 21-yard throw to A.J. Green with fourteen seconds remaining set up the game-winning field goal, propelling the Bengals to a 13–10 victory and a second consecutive berth in the NFL playoffs. This game marked the first time Dalton was able to defeat the divisional rival Steelers, and the first time the Bengals made the playoffs in consecutive seasons since 1981–1982. The following week, Dalton threw for a touchdown and a 101.5 quarterback rating in one half of play in a 23–17 Bengals win over the Baltimore Ravens. This marked Dalton’s first victory over the divisional rival Ravens and capped a 10–6 regular season record.

On January 5, 2013, Dalton and the Bengals faced the Houston Texans in the wild-card round of the NFL playoffs. In a defensive struggle with neither Dalton nor Texans quarterback Matt Schaub able to pass for a touchdown, the Bengals lost 19–13, the second consecutive year the Bengals fell to the Texans in the opening round of the playoffs. With 2:57 remaining in the fourth quarter, Dalton overthrew an open A.J. Green for what would have been the go-ahead touchdown.

On September 8, 2013, Dalton completed 26 of 33 passes for a career-high 78.8 completion percentage, 282 yards, two touchdowns, two interceptions (arguably neither interception his fault), and a 91.8 QBR as the Bengals fell to the Chicago Bears, 24–21. The following week, Dalton threw for 280 yards and a touchdown as the Bengals beat the Pittsburgh Steelers 20–10. Then, Dalton completed 20 of 28 passes for 235 yards, two touchdowns, and an interception for a 105.5 passer rating in leading the Bengals to a 34–30 victory over the Green Bay Packers.

On October 13, 2013, after two games without a touchdown pass (in a loss at the Cleveland Browns and a victory over the New England Patriots), Dalton rebounded by completing 26 of 40 passes for 337 yards, three touchdowns, and an interception for a 105.9 passer rating in a 27–24 overtime victory at the Buffalo Bills. For his efforts in that game, Dalton was named the AFC Offensive Player of the Week. Then, he completed 24 of 34 passes for 372 yards and three touchdowns for a 92.8 QBR and a 135.9 passer rating in leading the Bengals to victory at the Detroit Lions, 27–24. The following week, Dalton completed 19 of 30 passes for 325 yards, a career-high five touchdowns, and an interception in merely three quarters of play for a 125.7 passer rating and a career-high 98.9 QBR in a 49–9 win over the New York Jets. At the end of October, Dalton was named AFC Offensive Player of the Month.

On October 31, 2013, Dalton began another difficult two-game stretch. He passed for 338 yards at the Miami Dolphins but also had three interceptions, most critically one that bounced off the hands of Mohamed Sanu that if caught by Sanu likely would have sealed a victory for the Bengals, who ended up losing 22–20 in overtime; Dalton was sacked by Cameron Wake in the end zone in overtime for a safety to end the game. The following week, Dalton passed for 274 yards at the Baltimore Ravens with two touchdowns, most notably a 51-yard Hail Mary touchdown pass against the wind to A.J. Green as time expired in regulation, but also had three interceptions as the Bengals lost 20–17 in overtime. Dalton continued his struggles against the Cleveland Browns, as he threw two interceptions in the first quarter. However, he rebounded to throw three consecutive touchdowns as well, as the Bengals won the game 41–20. After an early interception at the San Diego Chargers, Dalton again rebounded by passing for 149 yards and a touchdown in the second half as the Bengals won 17–10.

On December 8, 2013, Dalton continued his upswing. He completed 24 of 35 passes for 275 yards and four total touchdowns against the Indianapolis Colts, attaining an 89.2 QBR and 120.5 passer rating in a 42–28 victory. Although the Bengals lost at the Pittsburgh Steelers the following week, Dalton was able to pass for 230 yards and two touchdowns while overcoming six dropped passes by his receivers. For the second time in the 2013 season, he earned AFC Offensive Player of the Week honors. Dalton continued his December success the following week by completing 27 of 38 passes for 366 yards and four touchdowns for a 92.0 QBR and a career-high 136.5 passer rating in defeating the Minnesota Vikings 42–14. With this game, Dalton and the Bengals became the 2013 AFC North Division Champions and Dalton had earned his third consecutive berth to the NFL playoffs, becoming just one of five NFL quarterbacks to make the playoffs in each of his first three seasons. While the Bengals beat the Baltimore Ravens 34–17 the following week, Dalton struggled, scoring three total touchdowns and passing for 281 yards but also four interceptions.

Dalton threw three interceptions in the first half during the home opener against the Baltimore Ravens in Week 1. Overall, he finished the game with 170 passing yards and had four interceptions as the Bengals were shut out and lost by a score of 20–0. Dalton’s four interceptions tied his career high for a single game, with the other instance occurring against the Ravens in a 2013 matchup. Though the Bengals were eliminated from playoff contention by the time of the rematch with Baltimore in week 17, Dalton threw a game winning touchdown pass to Tyler Boyd with 44 seconds left in the game, eliminating the Ravens from the postseason and allowing the Buffalo Bills to clinch their first playoff berth since 1999.

On August 4, 2014, Dalton received a six-year extension that could be worth as much as $115 million, with team performance-based incentives. He started the season with three wins. In Week 1, Dalton threw the game-winning 77-yard touchdown pass to A.J. Green to beat the Baltimore Ravens 23–16, Dalton’s first win on the road against the Ravens. In Week 3, he caught an 18-yard touchdown pass from Mohamed Sanu against the Tennessee Titans in a 33–7 victory. It was the first time a quarterback had caught a touchdown pass since former Chiefs quarterback Tyler Thigpen caught a 37-yard pass from wide receiver Mark Bradley in 2008. Dalton was the first quarterback ever to catch a touchdown pass for the Bengals.

On January 20, 2015, it was announced that Dalton was selected to the 2015 Pro Bowl, his second Pro Bowl appearance, replacing Aaron Rodgers of the Green Bay Packers (calf injury). Dalton completed 9 of his 20 passes for 69 yards.

Dalton failed to reach 200 yards passing for the first time in Game 9, a 10–6 loss to the Houston Texans. Despite 315 passing yards and two scoring drives in less than four minutes in the late fourth quarter to tie the game, the Bengals lost Game 10 to the Arizona Cardinals. Dalton bounced back with three touchdowns and a 121.4 rating in a Game 11 win over the St. Louis Rams, and a career-high passer rating of 146.8 in a Game 12 victory over the Cleveland Browns. Early in Game 13 on December 13, Dalton fractured the thumb on his throwing hand while tackling Stephon Tuitt after an intercepted shovel pass, missing the season’s final three games (replacement AJ McCarron was 2–1 with a 97.1 passer rating). Dalton finished the year with 3,250 yards, 25 touchdowns, and 7 interceptions. He was the first Bengal ever to throw for more than 20 touchdown passes with fewer than 10 interceptions in franchise history. Dalton’s 106.2 passer rating ranked No. 2 and his 8.4 yards per attempt ranked No. 3 among NFL quarterbacks in 2015. He was ranked 35th by his fellow players on the NFL Top 100 Players of 2016.

The Bengals’ season ended when they lost to the Steelers 18–16 on January 9, 2016 in the AFC Wild Card Round. Dalton had the cast for his broken thumb removed five days before the game, but did not play.

On September 13, 2018, in Week 2, Dalton threw four touchdown passes in the home-opener against the division rival Baltimore Ravens. All four touchdowns were in the first half, three of them were caught by A. J. Green. The Bengals would go on to win 34–23. In Week 12, Dalton suffered a thumb injury in the fourth quarter and did not return. It was revealed that he suffered torn ligaments in the thumb and was placed on injured reserve on November 26, 2018. In 11 games in the 2018 season, Dalton finished with 2,566 passing yards, 21 touchdowns, and 11 interceptions.

In Week 1 against the Seattle Seahawks, Dalton threw for a career-high 418 yards and two touchdown passes in the 20–21 loss. Following an 0–8 start to the season, Bengals head coach Zac Taylor announced that he would bench Dalton and start rookie Ryan Finley. After three games and three losses with Finley, Dalton was re-named the starting quarterback on November 25, 2019 for their upcoming game against the New York Jets. In the game, Dalton threw for 243 yards and a touchdown as the Bengals won their first game of the season 22–6. In Week 15 against the New England Patriots, Dalton threw for 151 yards, one touchdown, and four interceptions during the 34–13 loss. This was Dalton’s fourth career game with four interceptions. In Week 16 against the Miami Dolphins, Dalton threw for 396 yards and four touchdowns. Dalton scored 16 points in the final 29 seconds of regulation to force an overtime that the Bengals ultimately lost 38–35 to clinch the NFL’s worst record. In Week 17 against the Cleveland Browns, Dalton threw for 190 yards, one touchdown, and one interception. In addition, he had eight carries for 10 yards and a touchdown during the 33–23 win. After the game, Dalton said that if it was his last game as a Bengal, “It was good to end it taking a knee.” Dalton appeared in 13 games in the 2019 season and recorded 3,494 passing yards, 16 touchdowns, and 14 interceptions.

On April 30, 2020, after nine seasons with the franchise, the Bengals released Dalton after selecting Joe Burrow with the first overall pick in the 2020 NFL Draft.

On May 2, 2020, Dalton signed a one-year contract with the Dallas Cowboys worth $7 million, to be Dak Prescott’s backup for the season.