Formed in 2011, the British studio will reportedly handle all mobile and handheld versions of the franchise, though it is unclear if that includes recently-announced title Call of Duty Black Ops 2: Declassified.
The news was revealed by UK games industry expert Andy Payne, who described Activision as a "machine" in an interview with VideoGamer.
"Activision are a machine. They're very good, and you know what, what people don't realise with Activision is, the two studios working on the Call of Duty franchise are collaborative studios," he said. "That's unheard of. All the assets are reusable, so they're not wasting time.
"The two studios are saying, 'I need a tank, pull it off from the library'. And those assets are also going to be starting to be used by the mobile team, which is going to be based in Leeds."
Activision Leeds is the latest studio to be confirmed for Call of Duty, following the announcement that former Tony Hawk developer Neversoft was hiring for the franchise.
The team is hiring senior level designers specialising in both single-player and multiplayer for its involvement in Activision's first-person shooter series.
Watch a trailer for Black Ops 2 below: