His resignation takes effect at midnight Tuesday.
The resignation comes as it was revealed last week that the mayor was the subject of a probe by the FBI, which alleged in a search warrant affidavit that he had fed insider information to Angels executives in the stadium deal and arranged to have a helicopter bought registered in Arizona so he could save money on taxes.
The FBI alleges that Sidhu was hoping to get a $1 million-dollar campaign donation from the team. That never happened and the FBI says the Angels were unaware of the scheme, but this has been building for a while now.
"A fair and thorough investigation will prove that Mayor Harry Sidhu did not leak secret information in the hopes of a later political campaign contribution," Sidhu's Attorney Paul S. Meyer said in a statement. "His unwavering goal form the start has been to keep the Angels in Anaheim, so that this vibrant social and economic relationship would continue...
"Mayor Harry Sidhu has has always, as his foremost priority, acted in the best interests of the City of Anaheim, and he does so today. In order to continue to act in the best interests of Anaheim and allow this great City to move forward without distraction, Harry Sidhu has resigned from his post as Mayor effective May 24, 2022."
This comes as last week, three Anaheim City Council members called on Mayor Sidhu to resign amid the FBI corruption probe into his involvement in the proposed sale of Angel Stadium to team owner Arte Moreno.
READ MORE: Majority of Anaheim City Council members call on mayor to resign amid FBI corruption probe
"We need a fresh start, and we need it now, and that starts with the mayor's resignation, and I hope that the mayor will act in the best interest of Anaheim," said Anaheim Mayor Pro Tem Trevor O'Neil.
Sidhu has not been charged with a crime but is accused of soliciting $1 million in campaign contributions from an Angels representative in exchange for performing official acts that would finalize the stadium sale.
FBI investigator Brian Adkins' affidavit states on at least two occasions, Sidhu provided confidential city information to the Angels for use by the team in their negotiations with the city.
READ MORE: Anaheim mayor may have engaged in scheme to defraud California, Arizona and FAA: Affidavit
Sidhu's attorney, Paul Meyer, released the following statement, which reads in part: "A fair and thorough investigation will prove that Mayor Harry Sidhu did not leak secret information in the hopes of a later political campaign contribution."
The question still remains on who will take over the mayor's seat.
City council has 60 days to appoint a replacement, but there is also an election in November. To make things even more problematic, there is a city council meeting Tuesday, and as of now, the vacancy can't even be discussed because it's not on the agenda.
That can change with an emergency addition, but this is now a city in turmoil with the federal government investigating.
City News Service contributed to this report.