He initially avoided a second trial after reaching a plea agreement with the Mueller investigation, but that fell apart when prosecutors persuaded a judge that Manafort had been lying rather than co-operating.
Manafort served three months as Trump's campaign chairman, from June to August 2016, before he was forced to resign amid scrutiny of his previous work in Ukraine.
Prosecutors have recommended Manafort face decades in prison-essentially life sentence for the 69-year-old. They also pointed to Manafort's age and declining health.
Manafort will face sentencing next week on separate counts of witness tampering and conspiracy.
The prison term, handed down by U.S. District Court Judge T.S. Ellis III in a packed federal courtroom in suburban Virginia, is the first of two sentences for Manafort, who turns 70 next month.
While not apologizing for his actions, Manafort had asked Ellis for "compassion".
But he said the sentencing guidelines cited by prosecutors calling for between 19.5 and 24 years in prison were excessive.
But the judge also rejected Manafort's attorneys claims that the lack of any such evidence undermined the case, saying he had considered that issue at the beginning of the case.More news: German minister hails Macrons plan for ‘European renaissance
Manafort's "misconduct," prosecutors wrote, involved more than $16 million in unreported income (resulting in excess of $6 million in federal taxes owed), upward of $55 million stashed in hidden foreign bank accounts and north of $25 million secured from financial institutions "through lies resulting in a fraud loss of more than $6 million".
Government lawyers countered that Manafort's millions were built on a criminal enterprise in which he hid tens of millions of dollars in foreign income and failed to pay more than $6 million USA in taxes.
Also last month, Manafort's lawyers inadvertently revealed in a court filing that their client had shared polling data about the 2016 Trump campaign with Mr Kilimnik.
Ellis in Virginia has sentenced hundreds of defendants during his 30 years on the federal bench - and in a court that's typically considered tough on crime. Manafort has shown little remorse, they say, and even lied under oath following a plea deal after the trial.
Manafort volunteered to work for the Trump campaign for free.
In reality, they said, he was under Justice Department investigation before Mueller was appointed special counsel in May 2017. Mueller's prosecutors have so far not taken a position on what Manafort's sentence should be, although they are expected to weigh in during the Washington hearing on whether the sentences should be concurrent or consecutive.
The sentencing capped a stunning downfall for Manafort, a prominent figure in Republican Party circles for decades who also worked as a consultant to such global figures as former Angolan rebel leader Jonas Savimbi, former Philippine President Ferdinand Marcos and Yanukovych.
The verdict marked a dramatic fall for Manafort, a savvy political operative who advised US presidents as well as foreign leaders.