The Attorney General said that the Justice Department had filed a motion to unseal the search warrant and property receipt.
Garland made his first public statement about the search at Trump's Florida residence at a press conference.
Garland said that he personally approved the decision to seek a search warrant and that the department does not take such decisions lightly.
The former president's counsel received copies of the warrant and the FBI property receipt on the day of the search.
Multiple reports say that the raid was related to an investigation into Trump's handling of classified information. A federal grand jury is investigating whether he mishandled top- secret documents and took 15 boxes of them to a Florida resort.
Florida Politics reported that the FBI had executed a search warrant and left the premises minutes before Trump posted his statement on Truth Social.
The home of Donald Trump in Palm Beach, Florida is currently under siege by a large group of FBI agents. He decried the search as "prosecutorial misconduct, the weaponization of the Justice System, and an attack by the Radical Left Democrats who don't want me to run for President in 2024."
The search warrant was authorized by a federal court, according to Garland.
Republican lawmakers and conservative commentators jumped to the former president's defense after Trump's outrage, as he called for the FBI to be dismantled.
The rhetoric surrounding the Mar-a-Lago raid quickly turned violent. Within hours of Trump announcing the raid, users on more fringe platforms such as Gab and Telegram called for civil war and vowed to take up arms.
Garland wanted to address recent attacks on the professionalism of the FBI and Justice Department agents.
Garland will not be silent when their integrity is attacked. The men and women of the FBI are dedicated public servants. They protect the American people from violent crime and other threats to their safety every day. They risk their own lives to do so.
He said he was honoured to work alongside them.