John replaces Simon Hoggart, who wrote the Guardian's parliamentary sketch for 20 years until his death in January this year.
John first started writing for the Guardian in 2001 and is best known as the writer of the weekly Digested Read, which he will continue to write alongside his new role.
Alan Rusbridger, editor-in-chief, Guardian News & Media, said: "John has won a big following over the years for his writing, which is sharp, clever, wide ranging and very funny. He's stepping into big shoes - Simon Hoggart was the undisputed giant of his generation of sketchwriters. But I can think of no-one better than John to fill them."
John Crace said: "Simon Hoggart set the benchmark by which all other political sketchwriters are now judged. It is a huge and rather daunting honour to be asked to fill the gap he has left, but I am thrilled to have been given the chance. The political sketch is the dream job for any satirist: let the fun begin."
