Detroit ? Mayor Kwame Kilpatrick pleaded guilty to felony charges Thursday in a sex scandal, forcing him out of office after months of defiantly holding onto his job leading the nation’s 11th-largest city. He was ordered jailed for four months and fined $1 million.

“I lied under oath,” Kilpatrick said in court.

The plea deal brings to an end a seven-months-long ordeal that has been a distraction for one of the nation’s most troubled cities, which suffers from some of the highest home foreclosure and unemployment rates in the country, and has struggled for decades against population loss, high crime and racial tension.

The Detroit city charter automatically expels any mayor guilty of a felony.

A one-sentence letter signed by Kilpatrick and filed with the court states his resignation will take effect Sept. 18.

City Council President Ken Cockrel Jr. will succeed Kilpatrick as mayor until a special election is held.

As part of Thursday’s deal, the 38-year-old Democrat is to serve four months in jail and five years of probation. He also would pay the $1 million in restitution over the five-year probationary period, cannot run for any elected office for five years and loses his law license.

During a separate hearing moments after Wayne County Circuit Court Judge David Groner accepted the mayor’s plea, Kilpatrick offered a no contest plea in an assault case.

The judge also accepted that plea, which called for Kilpatrick to serve a four-month jail sentence that would run at the same time.

Kilpatrick had faced 10 felony counts in the two separate criminal cases.

Groner asked Kilpatrick if he understood he was giving up the right to be innocent until proven guilty.

“I gave that up a long time ago,” Kilpatrick replied.

The married mayor and former top aide Christine Beatty were charged in March with perjury, misconduct and obstruction of justice. They’re accused of lying under oath about an affair and their roles in the firing of a deputy police chief.

Beatty did not plead guilty and next will appear in court on Thursday. Groner said a plea deal in Beatty’s case appeared likely.

The mayor will be sentenced on Oct. 28. He will report to jail that day, said Wayne County Prosecutor Kym Worthy.

“We did not give an inch, and these conditions were basically to a letter of what we wanted all along,” she said.

Worthy said she was glad that Kilpatrick resigned but that was never a “bargaining chip” for her. She said paying restitution and serving time in jail were far more important.

“You don’t just lose your job and walk away,” she said.

Democratic Gov. Jennifer Granholm described the events of the day as “a sad but historic story” that’s coming to an end.

“A public office is entrusted to the person who holds that office but belongs to the people who are served by that office,” she said.

She also suspended a hearing that she had started Wednesday to determine whether he should be removed from office for misconduct. The proceedings were rendered moot.

Until now, Kilpatrick had refused to resign even as the calls for him to step down grew louder and the controversy overshadowed all else at City Hall, tarnishing the national image of the much-maligned city even more.

Kilpatrick leaves a mixed legacy. He persuaded big business to invest in a city staggering from the auto industry’s woes and a decades-long exodus of people, but he failed to live up to a promising political future because of repeated scandal.