Zoe, 39, welcomed her child with husband Rodger Berman on December 22.
"As loyal readers of The Zoe Report, I wanted you to be the first to see a picture of the beautiful new addition to our family, Kaius Jagger Berman, aka 'Kai'," she wrote.
"Rodger, Skyler and I are madly in love and will be happily hibernating for the next couple of weeks. Thank you for all of your kind words, as they mean so much to us," she added.
In the photo, Zoe sits in a hospital bed while cradling baby Kai and posing with Berman. Despite having just given birth, the fashion designer looks gorgeous with her hair and makeup done.