Former Prince George’s county executive Jack B. Johnson vowed Tuesday to fight federal bribery charges, saying he had devoted “every minute, every effort” of his tenure to the county’s residents.

“We’re going to fight,” Johnson said after entering a plea of not guilty in federal court in Greenbelt. “My reputation is at stake.”

Johnson, 61, a former prosecutor who was the county’s top elected official from 2002 to 2010, is accused of accepting more than $200,000 in bribes from a developer. Federal prosecutors in Maryland have said the charges are part of a far-reaching, six-year corruption probe that involves other county officials and business people.

Tuesday marked the first time Johnson has spoken publicly about allegations that he traded business permits, millions in grant funding and other favors for money. Court papers quote Johnson in wiretaps talking about shaking down developers and demanding money for his wife’s campaign for a seat on the Prince George’s County Council.

“I didn’t even recognize the person being charged,” Johnson said as he stood outside the U.S. District Court. He said he was “flabbergasted” and “extremely disappointed” by the charges.

“I gave every minute, every effort to the people of Prince George’s County,” Johnson said. He declined to provide specifics about his defense.

Johnson’s attorney, Billy Martin, said he will aggressively challenge the wiretap evidence, which is key to the prosecution’s case. He said he would review the FBI’s use of wiretaps to ensure that “all the laws were complied with.”

“We know the government has a five- or six-year head start,” Martin said. “This is the day we begin to fight these charges.”

During the brief arraignment, Johnson, who wore a dark, pinstriped suit, told the judge he understood the charges against him. On Johnson’s behalf, Martin entered a plea of not guilty to all eight charges. Martin requested a jury trial and a speedy trial, which means it must be held within 70 days.

Prosecutors said in court that the case involves “substantial amounts of wiretap evidence” and that they would share more of those conversations with the defense in coming days. According to court papers, FBI agents had been listening in on Jack Johnson’s cellphone since January 2010.

The Prince George’s corruption probe became public in November when Johnson and his wife, Leslie, 58, were arrested at their Mitchellville home and accused of conspiring to hide $79,600 in cash in Leslie Johnson’s underwear and to flush a $100,000 check from a developer down a toilet. At the time, both were charged with evidence and witness tampering.

The arrest occurred only weeks before Johnson, who was twice elected county executive, left office, and days after Leslie Johnson was elected to the County Council.

Leslie Johnson (D-Mitchellville), who is awaiting a preliminary hearing on charges of witness tampering, has maintained her council seat but has been stripped of some responsibilities.

Magistrate Judge William Connelly approved a request by Leslie Johnson to delay the hearing, which had been scheduled for Wednesday, to April 6. The judge said in an order that no further delays would be granted

Leslie Johnson is named as a co-conspirator in her husband’s indictment but has not been charged with bribery.

During his brief comments outside the courthouse Tuesday, Jack Johnson said many people have called to offer support, and he thanked them.

Morris Smalls, who grew up with Johnson in Charleston, S.C., and now lives in Bowie, attended the hearing and said he believes his longtime pal is innocent.

“I’m supporting him,” Smalls said while waiting for Johnson after the arraignment. “All of the things he did for the county, the whole county should be out here.”

Staff writer Cheryl W. Thompson contributed to this report.