The Canadian-born teenager headed home the game's only goal on 32 minutes to get the Gers' title celebrations up and running.
Berwick were competitive throughout and came close to an equaliser on a number of occasions, but despite the defeat they held on to clinch the final play-off spot.
The visitors applauded Rangers onto the pitch but showed little charity once the action got underway, their organised defensive system keeping the champions at bay.
David Templeton looked lively early on, although he fired a close-range free-kick harmlessly over the bar, while Kevin McDonald stung Neil Alexander's palms with a low-struck effort at the other end.
The game's first moment of real quality resulted in a goal, Aird timing his run perfectly to meet Kyle Hutton's inviting cross from the left wing and send the majority of the 50,048 crowd into raptures.
Rangers enjoyed the lion's share of possession but they suffered a scare in first-half injury-time when Damien Gielty's dangerous cross caused consternation in the hosts' defence, while Templeton came close to doubling their lead in the half's final piece of action.
Berwick went even closer on 53 minutes when Scott Dalziel met Steven Notman's looping cross, only for Alexander to produce a fine reflex save.
Lewis MacLeod and substitute Kane Hemmings fluffed chances to close out the game and Luca Gasparotto was stretchered off in injury-time, but Rangers held on to lift the league trophy on the back of a victory.