Karzai appointed Fazel Ahmad Manavi as the chairman of the Independent Election Commission (IEC).
The new appointment comes after several senior officials stepped down over allegations of vote fraud in last year’s presidential election.
Afghans will go to the polls again in September 2010 to elect a new parliament.
Manavi worked as a commissioner at the IEC during last year’s presidential vote.
He is also a professor of Islamic Sharia law and has held various government posts over the past nine years.