He attended Northwestern High School in Rock Hill, South Carolina, and was a letterman in football and track.

The two-time All-Region selection and Northwestern HS Student of the Year led his team to the state championship in his junior season.

[3] On March 18, 2004, Watson participated at Georgia's pro day, but chose to stand on his combine numbers and only performed positional drills and the 40-yard dash.

[4] At the conclusion of the pre-draft process, Watson was projected to a second round pick by NFL draft experts and scouts.

On August 14, 2004, Watson fired his agent Tom Condon, but was contractually obligated to retain IMG as his representative.

Head coach Bill Belichick officially named Watson the starting tight end to begin the regular season in 2004.

On October 9, 2005, Watson scored his first NFL touchdown off of a 33-yard pass by quarterback Tom Brady as the Patriots defeated the Atlanta Falcons 31–28 in Week 5.

On December 11, 2005, Watson caught three passes for 35-yards before exiting in the fourth quarter of the Patriots' 35–7 victory at the Buffalo Bills after suffering a concussion.

[16] During the game, Watson ran the distance of the football field to catch and tackle Champ Bailey at the Broncos' one-yard line after an interception in the Patriots' end zone, preventing a touchdown.

[21] On October 7, 2007, Watson caught six passes for a season-high 107 receiving yards and two touchdowns during a 34–17 win against the Cleveland Browns in Week 5.

On January 12, 2008, Watson caught two passes for 12-yards and two touchdowns in the Patriots' 31–20 win against Jacksonville Jaguars in the AFC Divisional Round.

On February 2, 2008, Watson started in Super Bowl XLII, but was held without a reception as the Patriots lost 17–14 to the New York Giants.

With Brady sidelined with a torn ACL, the Patriots started backup Matt Cassel and finished with an 11–5 record, but did not qualify for the playoffs.

He started the Patriots' season-opener against the Buffalo Bills and recorded a season-high six receptions for 77-yards and caught two touchdown passes during a 25–24 victory.

[31] On December 5, 2010, Watson recorded a season-high ten receptions for 100 receiving yards and a touchdown in the Browns' 13–10 win at the Miami Dolphins in Week 13.

[33] On July 30, 2011, Watson suffered a concussion after taking an inadvertent knee to the helmet during the Browns' first practice in training camp.

The following week, Watson caught a season-high six passes for 48 receiving yards and a touchdown as the Browns lost to the Tennessee Titans 31–13.

On October 23, 2011, Watson exited the Browns' 6–3 victory against the Seattle Seahawks at the beginning of the third quarter due to a concussion.

[34] In Week 14, he caught two passes for 11-yards, but suffered his third concussion of the season and exited in the second quarter of a 14–3 loss at the Pittsburgh Steelers.

[35][36] On December 16, 2011, the Cleveland Browns officially placed Watson on injured reserve, and he missed the remaining three games of the regular season after being evaluated by a head trauma specialist.

[38] In Week 11, Watson recorded four receptions for 47-yards and caught a season-high two touchdown passes in a 23–20 overtime loss at the Dallas Cowboys.

[42] Playing behind Jimmy Graham, Watson caught his first touchdown as a member of the Saints in week four on a four-yard pass by quarterback Drew Brees during a 38–17 win against the Miami Dolphins.

"[49] On November 1, 2015, Watson recorded nine receptions for a season-high 147 receiving yards and a touchdown in the Saints' 52–49 win against the New York Giants in Week 8.

[11][52][53] Throughout training camp, Watson competed to be the starting tight end against Crockett Gilmore, Dennis Pitta, and Maxx Williams.

[55] During training camp, Watson competed to be the starting tight end against Crockett Gilmore, Nick Boyle, and Maxx Williams.

[56] Head coach John Harbaugh named Watson the backup tight end on the depth chart to begin the regular season, behind Nick Boyle.

That season, Watson won the Bart Starr Award as the NFL player who "best exemplifies outstanding character and leadership in the home, on the field, and in the community.

[65] Watson made his 2019 debut on October 21 in a Monday Night Football matchup against the rival New York Jets which the Patriots won 33–0.

[75] On November 17, 2015, Watson released a book, Under Our Skin: Getting Real About Race--And Getting Free From the Fears and Frustrations That Divide Us, with Tyndale House Publishers.

[78] In 2018, Watson won the Bart Starr Award as the NFL player who "best exemplifies outstanding character and leadership in the home, on the field, and in the community.