Brown signed with the New England Patriots shortly thereafter but was cut after appearing in just one game, in which he caught a touchdown pass from Tom Brady in a dominant road victory over the Miami Dolphins.

After spending the rest of 2019 and beginning of 2020 as a free agent, he signed with the Tampa Bay Buccaneers, with whom he won Super Bowl LV over the Kansas City Chiefs.

After learning that Jones had left West Virginia to become the head coach at Central Michigan University, Brown enrolled at the school and started his college football career as a walk-on freshman.

[16] Transitioning from the quarterback position in high school to wide receiver in college was not that difficult for him, and after a few weeks, Central Michigan coaches offered him a scholarship.

[53][54] Brown participated at Central Michigan's Pro Day and decided to try to improve on his 10, 20, and 40-yard dash times after being unsatisfied with the numbers he clocked at the combine.

[60] Brown was named the Steelers' fifth wide receiver on their depth chart, behind veterans Hines Ward, Mike Wallace, Antwaan Randle El, and Arnaz Battle.

[61] On September 19, Brown made his NFL debut against the Tennessee Titans and returned two kickoffs and a punt for 128 yards, including an 89-yard touchdown from a reverse on the first play of the game, in the 19–11 victory.

[68] The following week in the AFC Championship against the New York Jets, at the two-minute warning, Brown caught a 14-yard pass on 3rd & 6, sealing the 24–19 victory for the Steelers and advancing them to Super Bowl XLV.

[70][71] Brown entered training camp competing with Emmanuel Sanders, Arnaz Battle, Limas Sweed, and Jerricho Cotchery to be the Steelers' third wide receiver after the departure of Antwaan Randle El.

[79] In a Week 14 win over the Cleveland Browns, he made his second start of the season and ended the game with five catches for a season-high 151 yards and scored a season-long 79-yard touchdown in a 14–3 victory.

[86] With the retirement of Hines Ward during the offseason, Brown entered training camp competing with Mike Wallace and Emmanuel Sanders to be the starting wide receivers.

[90] On November 4, Brown was fined $10,000 by the NFL for unsportsmanlike conduct when he ran backwards for the final 20 yards of a punt return touchdown the previous week against the Washington Redskins.

The ball was eventually tossed to Brown, who raced up the sideline for what appeared to be the game-tying touchdown until referees announced he had stepped out of bounds at the 13-yard line with no time left.

[104] On December 29, he, along with Pierre Garçon of the Washington Redskins, tied Jimmy Smith as the only players to record at least five receptions in every game of an NFL season.

[145][146][147] Brown started in the season opener against the Washington Redskins on Monday Night Football and finished the 38–16 victory with eight receptions for 126 yards and two touchdowns.

[148] After the game, the NFL fined him a combined $15,191 for wearing baby blue cleats, which violated the league's uniform policy, and for twerking after scoring his second touchdown.

[b] In the Divisional Round, Brown caught six passes for 108 yards in an 18–16 road victory over the Kansas City Chiefs, becoming the third Steeler with four or more 100-yard receiving playoff games.

[c] After the game, Brown broadcast the team's locker room celebration on Facebook Live in violation of NFL rules and despite the requests of teammates Ben Roethlisberger and Ramon Foster to "keep a low profile on social media".

[174] During a Week 4 26–9 road victory over the Baltimore Ravens, Brown became angry over not being thrown the ball by Ben Roethlisberger on an incomplete play, and was filmed throwing a Gatorade cooler and yelling at coaches.

[181] Plagued with a minor toe injury,[182] in Week 14 against the Ravens, Brown finished with a season-high 213 receiving yards on 11 receptions, helping the Steelers narrowly win 39–38 and clinch the AFC North title.

Shortly after the Steelers' 27–24 loss to the AFC East-clinching Patriots, it was revealed that Brown's left calf was partially torn, meaning that he would not play for the rest of the regular season, but would return during the playoffs.

[246] In the Wild Card Round against the Washington Football Team, Brown rushed once for a 22-yard gain and caught two passes for 49 yards and a touchdown during the 31–23 win.

[254][255] In Week 17, during the third quarter of the Buccaneers' 28–24 win over the New York Jets, Brown took his jersey, shoulder pads, glove, and shirt off and ran off the field into the locker room.

"[259] Tom Brady in the same press conference stated "We all love him, we care about him deeply, we wanna see him be at his best; unfortunately, it won't be with our team.

[268][269] On November 21, 2024, Brown released a statement coming out of retirement once again, expressing a willingness to play for the Pittsburgh Steelers for free for the remainder of the 2024 season.

I want to make it very clear that I am not the owner of this team, and any claims to the contrary are completely false.Media outlets disputed Brown's self-reference as a "foreign national", since both of his parents are U.S. citizens, and he was born and raised in Miami.

[288] During his first month of class, Brown was the target of ridicule after he asked his 6.2 million Twitter followers for help proofreading an English paper, which was due that evening, in a tweet with several spelling and grammar errors.

This included tossing furniture out of his 14th-floor apartment window in April, nearly hitting a 22-month-old toddler on the patio below,[295] and being cited for speeding, driving in excess of 100 miles per hour (160 km/h) along a suburban Pittsburgh road.

[310][311][312] On December 1, Tampa police attempted to serve Brown with an arrest warrant on domestic violence charges related to an incident with his ex-fiancée on November 28, in which he threw a shoe at her during an argument with her.

A source told the Times Union that the hotel asked Brown to leave due to complaints of loud music and marijuana smoking.