"The defendant is not public enemy number one," US District Court Judge Amy Berman Jackson said in delivering the sentence in a hushed Washington courtroom.
"But he is not a victim either," Jackson added, stressing that the veteran Republican lobbyist and political consultant had shown little remorse and had lied repeatedly.
Manafort's case is the highest-profile yet stemming from Special Counsel Robert Mueller's investigation into Russian interference in the 2016 presidential election.
Jackson stressed to the court that the case had nothing to do with the 2016 vote but was connected to political consulting and lobbying activities he performed for pro-Russian Ukrainian politicians.
She said the question of whether any members of the Trump campaign colluded with Russia was "not presented in the case. Period."
"Therefore it was not resolved in this case either," Jackson said.
She ridiculed defense arguments that Manafort's prosecution only came about because of the Mueller probe.
"That argument falls flat," Jackson said. "The Department of Justice was already looking into this matter."
Before his sentencing, Manafort, who was brought into court in a wheelchair, pleaded to the judge not to sentence him to more time other than the 47 months he was given last week in a separate case.
"I am sorry for what I have done and all the activities that have got me here today," Manafort told the court.
"Let me be very clear I accept responsibility for the acts that have got me here today," he went on. "For those mistakes, I am remorseful."
But Jackson dismissed his plea for no more prison time on the charges of conspiring to launder money and tamper with witnesses.
She added 43 months to the 47 months he already received, making the total 90 months. She gave him credit for the nine months he has already spent in prison, reducing the term facing him to 81 months -- a little under seven years.
Manafort is one of a half-dozen former Trump associates and senior aides charged by Mueller, although none of them have been accused so far of direct collusion with Moscow to get Trump elected to the White House.
Manafort has already been sentenced to 47 months in prison for tax and bank fraud. The new sentence is for conspiracy.