The veteran, who always gives value for money, came off worse when trading with the tough Pole and had to take counts in the second (twice), tenth and twelfth.
In certain rounds, Cunningham proved he could still cut it at 200 pounds following a spell at heavyweight, although Glowacki always had that little extra in his locker and saw out a wide decision on the cards.
Judges came back with scores of 116-108 and 115-109 (twice) as Glowacki made a successful first defense of the belt he took from Marco Huck so impressively last year.
Glowacki, who extends to 26-0, had halted Huck’s run of title defenses just one shy of breaking British ex-champion Johnny Nelson’s previous record of thirteen.
Earlier on the New York bill, lightweight prospect Mario Barrios kept up his unbeaten run with a points victory over eight rounds, whilst Heather Hardy stopped Anna Hultin in the fourth session.
Super welterweight Lukasz Maciec, cruiserweight Earl Newman and welterweight Radzhab Butaev all had their hands raised on the Premier Boxing Champions card after featuring on the off-TV portion of the event.