The British actor, 44, will take on the character created by JK Rowling and played on the big screen by Richard Harris and then Michael Gambon, Warner Bros confirmed on Wednesday.
According to studio president Toby Emmerich, Law will portray Dumbledore in his younger years, before he became the white-haired headmaster of Hogwarts.
The action will follow the character during his time as the wizarding school’s Transfiguration professor.
“As fans ourselves, we are thrilled to have Jude Law joining the ‘Fantastic Beasts’ cast, playing a character so universally adored," Emmerich said in a statement.
"Jude has been a member of the Warner Bros. family for years and we’re excited to embark on this new adventure with him.”
Director David Yates added: “Jude Law is a phenomenally talented actor whose work I have long admired, and I’m looking forward to finally having the opportunity to work with him.
“I know he will brilliantly capture all the unexpected facets of Albus Dumbledore as J.K. Rowling reveals this very different time in his life.”
Fantastic Beasts was a box office hit when it was released last year, grossing over $813 million at the global box office.
JK Rowling has since confirmed that there will be five films in the franchise, following its success.
Law will star opposite Johnny Depp, who will reprise his role as the villainous Gellert Grindelwald.