He was convicted last year of hiding millions of dollars of income earned by his political consulting in Ukraine.
He is due to be sentenced in another case next week related to his illegal lobbying.
The charges stem from an inquiry into whether the Trump campaign colluded with Russia to win the 2016 election.
US Department of Justice Special Counsel Robert Mueller is thought to be finishing up his 22-month investigation, which has dogged the Trump presidency.
Manafort - who will receive credit for time served - must also pay $24m (£18m) in restitution and a $50,000 fine.
The 69-year-old addressed the court on Thursday evening in Alexandria, Virginia, saying "the last two years have been the most difficult of my life".
"To say I am humiliated and ashamed would be a gross understatement," he added, asking the judge to be "compassionate".
He described his life as "professionally and financially in shambles".
Judge TS Ellis said he was surprised that Manafort did not "express regret for engaging in wrongful conduct".
Nevertheless he said sentencing guidelines cited by prosecutors calling for between 19.5 and 24 years in prison were "excessive".
The formerly dapper lobbyist - who entered the court wearing a green prison jumpsuit and in a wheelchair - was impassive as he learned his fate.
His legal team has previously said he suffers from debilitating foot pain resulting from gout as a result of his incarceration.
Manafort has been held in solitary confinement for the last nine months at a local jail since his bail was revoked for alleged witness-tampering.
His sentencing marks a spectacular downfall for a high-rolling Republican political guru who advised four US presidents, including Mr Trump, and foreign leaders.