Bernd Lucke, founder of the AfD, won broad backing on Saturday from the around 1,700 party faithful gathered in the northwestern city of Bremen for one leader to head the party instead of three, which he said was "amateurish".
The former economics professor said the pared-down structure would help make things more professional, telling delegates the two-year-old party was "not a skittles club or rabbit breeding association, which one can lead part-time".
Lucke, the AfD's most high profile figure, faces allegations from within the party of trying to extend his personal power through the reform, which will see two leaders from April, dropping to a single party chief from December.
The AfD's main battle cry when it was founded in early 2013 in the wake of the financial turbulence that almost brought the eurozone to its knees was for an orderly dissolution of the euro.
It narrowly missed entering the German parliament in the 2013 general election.
But it made a breakthrough last year by winning seats in the European Parliament and three German state assemblies after the party sought to widen out its appeal, incorporating populist issues such as law and order, immigration and traditional social values.
It now hopes to enter Hamburg's city-state assembly in a February 15 vote.
The party, which invited experts to the Bremen conference to speak on tax, social and health issues, plans to finalise its programme of policies in November.
But Lucke made clear he wanted to position the party, which analysts say is made up of three factions - neo-liberal, national conservative and a hard-right populist wing - in the political centre.
He also supported the call by Greece's new anti-austerity government for a debt writedown, saying on Sunday that there was "no way around it" but that Athens must quit the eurozone in return.