Defender Auston Trusty has joined the club in a permanent transfer from Colorado Rapids as transfer deadline day ticks down.
The 23-year-old will remain with the MLS side on loan until at least the end of the Premier League season in May.
The deal for Trusty, 23, comes with the helping hand of the Kroenkes, who own both clubs and have been keen to arrange a transfer for some time.
The USA U20 international joined Colorado Rapids from Philadelphia Union in November 2019. He made 41 appearances, helping the Rapids finish top of the Western Conference in the 2021 MLS regular season.
An Arsenal statement said: "The intention then is to loan him in Europe for the 2022/23 season to further progress his development."
The transfer is subject to the completion of regulatory processes.