US attorney Michael Garcia, whose past responsibilities have included enforcing arms regulations and money laundering statutes, was elected to probe allegations of corruption as head of the investigative chamber of FIFA's ethics committee.
German judge Hans-Joachim Eckert, presiding judge of the Munich penal court, will be responsible for judging cases and handing out sanctions as head of the investigative branch.
Garcia was immediately asked to re-examine the details of the case involving ISL, FIFA's former marketing company, by FIFA president Sepp Blatter.
"He (Garcia) will have not only the right but the duty to have this case analysed on ethical and moral grounds and then to report back to the executive committee," Blatter said.
"The chairmen of both chambers are totally independent, this had been requested by FIFA's Congress."
Blatter said that Garcia would also be able to investigate other allegations of wrongdoing in the past with no statute of limitations.
This could involve the controversy which surrounded the awarding of the 2022 World Cup to Qatar
Garcia was elected by FIFA's executive committee ahead of leading international prosecutor Luis Moreno-Ocampo, the other candidate for the post, by FIFA's executive committee.
His appointment came one week after the long-awaited release of court documents from the ISL case
A Swiss prosecutor said in a legal document released last week that former FIFA President Joao Havelange and former executive committee member Ricardo Teixeira took multi-million bribes on World Cup deals in the 1990s.
The bribes were paid by ISL, which collapsed in 2001. Blatter was general secretary under Havelange and attention has centred on whether he knew about the payments.
Havelange is FIFA's honorary president while Teixeira quit as head of the Brazilian Football Confederation this year.
During the media conference, Blatter shrugged off questions from German reporters over suggestions that he should resign following release of the court documents.
Blatter also caused huge offence in Germany by implying in a newspaper interview that the rights to host the 2006 World Cup in the country might have been "bought".
"You have to live with that," said Blatter. "The way the media sees me or judges me, that's their businesses."
"I'm elected by the 209 member confederations of FIFA and if they no longer want me, then I will of course say thank you and I will ask no questions. But it has to be done by Congress."