"Thank you SteelerNation for a big 9 years ... time to move on and forward," Brown tweeted with the hashtag #NewDemands.
ESPN's Adam Schefter said Brown officially informed the team he wants to be traded.
Brown, a four-time All-Pro, has been embroiled in a dispute with the Steelers, who openly have discussed the possibility of trading him.
Brown has three years remaining on a five-year, $72.7 million contract extension that he signed before the 2017 campaign. He has surpassed 100 receptions and 1,000 receiving yards in each of the past six seasons, and in 2018 he caught 104 passes for 1,297 yards and a career-high 15 touchdowns.
Brown's tweet and request came on the same day he was found guilty of reckless driving after failing to show up for his trial, multiple Pittsburgh media outlets reported.
Police cited Brown for driving a black Porsche in excess of 100 mph through Ross Township, Pa., on Nov. 8, which was the morning of the Steelers' game against the Carolina Panthers.
Reckless driving convictions in Pennsylvania carry maximum penalties of 90 days in jail, a $200 fine and a six-month license suspension.
An attorney for Brown left the courtroom without comment, according to WPXI.
It's the latest in a headline-producing few months for Brown, on and off the field.
Brown allegedly pushed the mother of his daughter to the ground last month in Hollywood, Fla., according to a police incident report. The woman did not press charges and Brown was not arrested.
It also came out that Brown was hit with two lawsuits in October for an incident that allegedly occurred at his South Florida high-rise last April.
Brown was accused of yelling at security personnel and throwing furniture from his balcony, upset over $80,000 and a gun he reported missing. Brown accused building security of being behind the alleged theft, according to police reports.
Brown was not charged in that incident either and has expressed his innocence.
One lawsuit claims that Brown just missed hitting a 22-month-old boy with the furniture.
--Field Level Media