Former Illinois Governor Rod Blagojevich has been found guilty of lying to agents.
A federal jury in Chicago found him guilty of making false statements but was unable to reach a unanimous verdict on 23 other corruption charges.
The judge said he intended to declare a mistrial on the remaining counts.
Blagojevich, 53, was accused of trying to use his office for personal gain - including a bid to sell President Barack Obama's vacant Senate seat.
He was also accused of attempted extortion.
After the verdict was announced, US attorneys said the government planned to retry the case "as quickly as possible".
Judge James B Zagel has set a hearing for 26 August to decide the timing of the retrial.
Before jurors came in, a sombre-looking Blagojevich sat with his hands folded, looking down.
He showed no emotion as the verdict was read, but his wife, Patti, leaned over and shook her head.
Speaking afterwards outside the court, Blagojevich was defiant.
"This jury shows you that the government threw everything but the kitchen sink at me," he said.
"They could not prove I did anything wrong - except for one nebulous charge from five years ago."
His lawyer said he would appeal against the conviction.
The verdict came on the jury's 14th day of deliberations.
Blagojevich's brother, Robert, is a co-defendant in the trial.
The one charge on which Blagojevich was found guilty was that he lied to federal agents when he said he did not track campaign contributions and that he kept a "firewall" between his political campaigns and his government work.
The charge carries a sentence of up to five years in prison.
The case involved hours of conversations wire-tapped by the FBI.
Defence lawyers had maintained that Blagojevich's talk was mere bluster and he had done nothing illegal.
Blagojevich, a Democrat, was ejected from office by the Illinois state legislature in January 2009.