The highly-rated young forward rejected a scholarship offer with the Black Cats and instead agreed terms to join the Gunners, with a professional deal set to be agreed when Greenwood turns 17 in the New Year.
Speculation regarding Greenwood, who was also linked to Manchester United, has been present for some time and the player himself confirmed a move earlier this week on social media, thanking Sunderland for his time at the club.
In a brief statement, Sunderland wrote:
“He expressed his desire to join Arsenal and we therefore moved quickly to bring the matter to conclusion, believing a swift resolution to be in the best interest of both Sam and the club. Terms were agreed with Arsenal and everyone at Sunderland AFC wishes Sam the very best of luck for the future as he embarks on the next stage of his football career.”