Brown reportedly signed a one-year, $15-million contract that also contains a team option for 2020 valued at $20 million.
Brown will be eligible to make his Patriots debut in Week 2 against the Miami Dolphins. The 31-year-old joins New England after a drama-filled six months with the Oakland Raiders, who released him two days before their season opener.
The mercurial Brown notched 104 receptions for 1,297 yards and a league-high 15 touchdowns receiving last year with the Steelers. He led the NFL in receiving in 2014 and 2017 and has earned seven Pro Bowl nods.