The former Sweden international, who was a member of the Gunners' 'invincibles' team of 2003-04, will be a figurehead in the club's plan for international growth
The 36-year-old will return to the club as a figurehead in international growth, hoping to help the Gunners reach out to more fans around the globe.
The former Sweden international midfielder will begin working with the club on a trip to Asia next week to promote the Gunners' pre-season tour of the region.
Arsenal’s head of marketing, Charles Allen, told the club's official website: "We are delighted that Freddie has agreed, in this ambassadorial role, to help us reach more of our passionate supporters around the globe. He is much loved by our fans and it’s great to have him back."
Ljungberg was a member of the Arsene Wenger's historic Arsenal side which went through an entire Premier League season undefeated, and was also a losing finalist with the Gunners in the 2006 Champions League final.
The Swede holds the distinction of being one of only three players in the history of the FA Cup to score in consecutive finals of the competition.
In total the midfielder, who also represented West Ham, Celtic, and Chicago Fire, made 216 appearances for Arsenal, scoring 46 goals.