The agency picked up the account following a three-way pitch against the regional agencies Driven and Love.
The business came up for pitch in May this year, when TBWA\Manchester resigned the account. The agency cited creative and strategic differences for the split.
Jan McKee, the marketing director at Chicago Town's parent Schwans, said: "This is an incredibly exciting time for us - we have ambitious plans to move the brand forward."
Jane Clancy, the managing director at Cheethambell JWT, said: "Chicago Town is a fantastic brand, bursting with ambition and personality."
Earlier this year, Chicago Town extended its sponsorship of ITV2's American Idol.