Balogun, the American leader with three goals, received a red card for stepping awkwardly on the right ankle of Tarik Muharemović of Bosnia and Herzegovina in a 2-0 round of 32 win on Wednesday (Thursday AEST). A red card triggers an automatic one-game suspension.
FIFA announced on Sunday (Monday AEST) that the suspension had been lifted, triggering praise from Trump and outrage from Belgium's team.
Trump called FIFA president Gianni Infantino after the game asking FIFA review the red card, according to a person familiar with the call who spoke on condition of anonymity because the person was not authorised to speak publicly about the matter.
"Thank you to FIFA for doing what was right, and reversing a great injustice!" Trump said in a statement on social media.
The Royal Belgian Football Association (RBFA) said it was "astonished" and Belgium coach Rudi Garcia mocked FIFA's action.
"I didn't know that in the offices of FIFA the 5th of July was the 1st of April in Europe," Garcia said through a translator in an April Fools' Day comparison.
"The Belgian federation does not defend itself, it does not protect the national team. She defends football in general, she defends her integrity, her ethics. I think it's the first time in the history of the World Cup that there is this kind of decision."
Garcia wouldn't respond when asked about a possible appeal to the Court of Arbitration for Sport or whether he thought Trump impacted FIFA's action.
"In order to safeguard the legitimate rights of all participating teams and to protect the fundamental principles of fair play in our sport, both at this FIFA World Cup and at future editions of the tournament, the RBFA is investigating all potential options," the Belgian federation said in a statement.
Balogun's red card had been one of the World Cup's most controversial and consequential decisions.
"If you look at the foul, it was just zero intent at all," US star Christian Pulisic said. "I felt like there was much worse ones that went on this tournament."
The US Soccer Federation learned of FIFA's action in a message sent by FIFA in its portal on Sunday morning.
"The implementation of the match suspension is suspended for a probationary period of one year," FIFA announced.
"If Folarin Balogun commits another infringement of a similar nature and gravity during the probationary period, the suspension shall be revoked and the sanction enforced without prejudice to any additional sanction imposed for the new infringement."
A 25-year-old who plays for Monaco, Balogun scored 13 Ligue 1 goals last season. He has 12 goals in 30 international appearances. He was born in Brooklyn to Nigerian parents who were living in London and in 2023 opted to change his national team affiliation from England, which he had represented at the under-21 level.
FIFA said its decision relied on Article 27 of disciplinary committee rules.
"The judicial body may decide to fully or partially suspend the implementation of a disciplinary measure. By suspending the implementation of the sanction, the judicial body subjects the person sanctioned to a probationary period of one to four years," the rule states.
FIFA in November deferred the final two games of a three-match ban for Portugal's Cristiano Ronaldo for a red card against Ireland in a World Cup qualifier, allowing him to play at the start of the World Cup.
