Arsenal technical director Edu has revealed Matt Turner was a long-term target for the club.
The 23-year-old completed his switch from New England Revolution on Monday, with the clubs having agreed a deal back in January.
Edu told the club's website: "We are delighted that Matt is joining us. Matt is a goalkeeper with established qualities and experience, who will be a great addition to our squad.
"We identified Matt some time ago and worked hard to ensure that his transfer was complete so he could join us in time for our pre-season in July.
"We now look forward to Matt joining us, settling into his new home and working ahead of next season."
Matt made 102 appearances for the Revolution during his six years with the MLS side, and he will now compete with Aaron Ramsdale for a starting spot in Mikel Arteta's side.