The 39-year-old marketer has been with InBev for 10 years in total. During his time in the UK, he was responsible for the launch of Beck's Vier and the introduction of the new family of Artois beers, including Peeterman Artois.
Kelly was also responsible for the "Pass on something good" advertising campaign for Stella Artois, which broke last month. The TV ad, created by Lowe, focuses on the brand's six centuries of brewing history, to back the Stella Artois, Peeterman Artois and Artois Bock family of brands.
He was also said to be instrumental in increasing Tennent's Lager's market share in Scotland.
Kelly will return to the US in February, and InBev UK will start the search for a replacement immediately, considering both internal and external applicants.
Kelly said: "I have loved my time here in the UK with In Bev -- who wouldn't with such a magnificent portfolio of beers to work on. But for family reasons, I have decided that home is where the heart is, and that means a return to the good old US."
During his time at InBev, Kelly worked at Labatt USA, where he was director of marketing for Canadian brands and director of innovation.
He moved to InBev's Belgian headquarters in 2003 as global director of new brands before becoming global director for Brahma and Stella Artois.