Bernie Ebbers, who is 63, was convicted Tuesday on all counts of what is called the largest corporate fraud U.S. history.
After eight days of deliberation, a federal jury convicted the former WorldCom chief of engineering the colossal accounting fraud that collapsed the telecommunications giant.
The conviction comes more than two years after an internal auditor began asking questions about curious accounting at WorldCom, touching off a scandal that eventually unearthed $11 billion in cooked books.
The trial came down to one man's word against another's. Former WorldCom financial chief Scott Sullivan was the star witness against Ebbers.
Sullivan himself pleaded guilty to fraud, but claimed he did it on the clear instructions of Ebbers, who he said ignored his repeated pleas that the accounting adjustments were wrong.
Ebbers himself took the witness stand late in the trial, insisting that he was unfamiliar with the details of accounting and knew nothing about the fraud taking place on his watch.
Ebbers' defense team will appeal.
"He obviously wasn't vindicated today because I think the system works right. I expect him to be vindicated in the future after some of the errors made in the trial are remedied in the post-trial process," said Ebbers' attorney, Reid Weingarten.
Ebbers faces up to 85 years in prison. Sentencing is set for June 13.