United States Soccer Federation will vote for Prince Ali bin al-Hussein in Friday's FIFA presidential election.
US Soccer president Sunil Gulati confirmed the endorsement via Twitter as Prince Ali vies to replace Sepp Blatter at world football's governing body.
Prince Ali - the Jordan federation president - is one of five candidates alongside favourites Gianni Infantino and Sheikh Salman bin Ebrahim al-Khalifa, and Jerome Champagne and Tokyo Sexwale at FIFA headquarters in Zurich.
"@ussoccer will vote for @AliForFIFA for President of #FIFA," Gulati wrote on his official account.
Prince Ali, who lost out to Blatter in last year's vote, then replied: "I am proud to receive the support of @ussoccer, joining my vision for a new, transparent, fair and honest #FIFA that puts football first."
Football Federation Australia (FFA) has already announced its intention to back Prince Ali in the vote.
Prince Ali has been outspoken heading into arguably the biggest day in FIFA's history.
Amid the allegations of corruption that have engulfed the organisation, Prince Ali had hoped for transparent voting booths to be used during Friday's election to ensure a fair and open process in the Swiss capital, though his appeal was rejected by the Court of Arbitration for Sport (CAS).