Trenton Mayor Tony Mack, 48, had fought to remain in office until his sentencing in May while also seeking to have his conviction thrown out.
But Judge Mary Jacobson rejected his arguments and signed an order removing him from office. Mack is also ineligible to hold public office in the future and has been stripped of his taxpayer-funded pension. He will be allowed to keep the contributions he made to his retirement plan.
Mack did not speak during or after the hearing and his lawyer, Mark Davis, said it had not been decided whether he would appeal Wednesday's order.
Within hours after Jacobson signed an order removing Mack, City Council President George Muschal was sworn in as acting mayor. The 66-year-old retired city police officer is expected to serve out Mack's term, which ends July 1. He reiterated Wednesday that he does not intend to run in the regularly scheduled mayoral election on May 13.
"You can't move a city forward when there's full-blown corruption," Muschal told reporters at City Hall after he was sworn in at a hastily organized private ceremony in his office.
He vowed to be open with residents and the media and to support whoever is elected in the May election.
Muschal also said he would try to meet with Gov. Chris Christie and get the state's help for the city, including a request to hire 50 new police officers.
David Ponton, a Trenton resident who once led an effort to recall Mack, greeted Muschal after he was sworn in.
Ponton said in an interview that Muschal can help restore the city after the damage he said Mack did.
"When we elected a criminal, the criminals said, 'They're not going to send him to jail. I'll keep doing what I'm doing,'" Ponton said.
Mack was convicted Feb. 7 of bribery, fraud and extortion in a sting operation involving a bogus land development deal. His brother, Ralphiel Mack, a former high school football coach, was also convicted of participating in a scheme to take bribes in exchange for helping get approvals to develop a downtown parking garage.
Tony Mack's administration had been under a cloud since he took office in 2010 as Trenton's first new mayor in 20 years.
The state government took a role in city hiring decisions after charges of rampant cronyism and financial mismanagement. There was also rapid turnover at key city government jobs. Since deep layoffs in the city police force, crime in the city of 84,000 - one of the nation's poorest state capitals - has been a major problem. Last year, there were a record 41 homicides, including two men shot by police during confrontations.
After years of complaints about safety problems at the crumbling Trenton Central High School, state officials this year moved toward using state money to put up a replacement building for the city's only traditional public high school.
Davis, Mack's lawyer, argued Wednesday that the mayor should not be removed until he is sentenced, saying the conviction is not final until the sentence is imposed.
Public officials convicted of crimes of "dishonesty" in state court can be removed by the judge once their convictions are handed down. But for those like Mack convicted in federal court, the process can be more cumbersome.
"It's unfair for state officials, and it's primarily unfair for the people of the city of Trenton where their mayor has been convicted in federal court," Deputy Attorney General Steven Yomtov told the judge.
Muschal can now void actions taken by Mack in the time after he was convicted.
City Clerk Richard Kashmar, who sat in the front row of Wednesday's court hearing, said Mack only handled routine business and did not sign or veto any ordinances, so there's nothing that would need to be struck.
Mack joins a string of New Jersey mayors convicted in corruption cases since 2000 that included the leaders of Newark, Camden and Asbury Park.
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