The only way corruption like this can  be defeated by a president who is different from other leaders who have served in the past, is if the citizens of that country can fully support and stand by their president. If other bad politicians sees that majority  of the citizens  are against corruption,  I think it will be tough for them to go against the president.
 Like in South Africa,  it was easy for Nelson Mandela  to fight for good governance because  he was fully supported by other citizens  of South Africa .