He once held an official position within the Protestant church.
Arthur Wagner’s departure has caused a minor media sensation.
The party calls for a crackdown on asylum seekers and has said that Islam is not compatible with German values.
Harris Media’s website lists Ted Cruz, Rand Paul, Sarah Palin, and Britain’s pro-Brexit UKIP party among its past clients.
A speech by Bjoern Hoecke, the AfD's leader in the eastern state of Thuringia, on Tuesday triggered anger across Germany and even caused one member of the radical Left party to report him for incitement to racial hatred.
"They want to go back to the repressed West German republic of the 1960s," Sigmar Gabriel said.