The newlyweds told People.com, "We are overwhelmed with complete happiness and love having made our eternal commitment. To say 'I do' in front of family, friends and, most importantly, our children has been the happiest moment of our lives."
Simpson wore a custom Carolina Herrera gown, and the two shared their vows in front of more than 250 guests, including Jessica's sister, and her fiancé Evan Ross, and others.
The couple's son, Ace, 1, served as a ring bearer and daughter Maxwell, 2, as a flower girl, while Jessica's 5-year-old nephew, Bronx, walked with Maxwell down the aisle.
Simpson and Johnson have been engaged since 2010.