"It's official, after 11 years together ... Married the best man I've ever known," he tweeted along with a photo.
The ceremony took place Saturday in the Hamptons just as Jackson, 36, once imagined.
"[We want] something small ... just close friends and good music," he previously told NBC New York. "Our dog would be there. Our dog, our daughter, Zora. ... Pretty boring, but something just nice and on the beach."