The network announced Thursday that 47-year-old news correspondent's show, Tucker Carlson Tonight, will move from 7 p.m. to 9 p.m. following Kelly's departure.
"In less than two months, Tucker has taken cable news by storm with his spirited interviews and consistently strong performance," 21st Century Fox executive chairman Rupert Murdoch said in a statement.
"Viewers have overwhelmingly responded to the show and we look forward to him being a part of Fox News' powerful primetime line-up."
Martha McCallum will move into the 7 p.m. slot with a new program, The First 100 Days, centered on Donald Trump's presidency. She will also co-anchor the network's Inauguration Day coverage Jan. 20 with Bret Baier.
"Martha is a versatile and skilled anchor who has proven to be an essential component of our news programming," Murdoch said. "For the last 12 years, our viewers have trusted her reporting and we are pleased she will be part of our primetime line-up for the first 100 days of the new presidency."
"Congratulations to my friend @TuckerCarlson on moving to the 9p slot at Fox! This is a great decision by FNC & I will be cheering him on!" Kelly tweeted. "And congrats to the always classy @marthamaccallum on moving to the 7p! She's amazing & will shine at any hour."