White has signed a long-term deal at the Gunners in a move that was completed on Saturday (AEST).
Sorry we're late...— Arsenal (@Arsenal) July 30, 2021
Traffic was a nightmare 😉 pic.twitter.com/sO1T9981Rw
The 23-year-old had agreed a four-year deal with Brighton in 2020 after impressing on loan with Leeds United in the 2019-2020 season.
White went on to establish himself as a key part of Graham Potter's side, making 36 Premier League appearances last term.
His form was rewarded with a call up to England's provisional squad for UEFA Euro 2020, with White then replacing the injured Trent Alexander-Arnold in Gareth Southgate's 26-man selection.
While he did not make an appearance at the European championship, Arsenal has nevertheless committed to a huge outlay on the youngster.
Mikel Arteta's side is short at the back having allowed David Luiz to leave upon the expiration of his contract.