Roger Stone, long-time adviser and ally to President Donald Trump, has been sentenced to 40 months in jail.
Stone, 67, was found guilty in November on seven counts of lying to Congress, obstruction and witness tampering.
He is the sixth Trump aide convicted in a criminal case resulting from Robert Mueller's investigation into alleged collusion between Russia and the Trump campaign during the 2016 election.
Mr Trump has hinted he may pardon his ally.
Stone has maintained the case against him was politically motivated.
Explaining the sentence, Judge Amy Berman Jackson said Stone had engaged in "intolerable" "threatening and intimidating conduct" toward her.
Last week, prosecutors on the case quit after the Justice Department said it planned to reduce the amount of prison time sought for the president's long-time ally.
The prosecutors had recommended a sentence of seven to nine years.
In a tweet, Mr Trump had called the recommendation "very horrible and unfair".
The court heard that Stone had told five lies under oath, including about his conversations with Trump campaign officials and a supposed "intermediary" with WikiLeaks in early August 2016.
He also lied about the existence of certain texts or emails.
Speaking in a Washington courtroom on Thursday, Judge Jackson said Stone "knew exactly what he was doing" when he posted an image to social media last year of a gun sight over the judge, calling the proceedings a "show trial".
"This is intolerable to the rule of justice," Judge Jackson said. "The court cannot just sit idly by and say 'that's just Roger being Roger.'"
Stone told the court that he thought the crosshairs in the picture he posted of Judge Jackson on Monday actually depicted a Celtic cross.
"I am kicking myself over my own stupidity but not more than my wife is kicking me," he said.
Stone, wearing sunglasses and a dark fedora, declined to speak at Thursday's hearing.
His lawyer, Seth Ginsberg, said Stone's public persona – that of a self-described "dirty trickster" – masked the true "human being", a spiritual man, devoted to his family.
Mr Ginsberg had argued that Stone did not deserve the tougher sentencing guidelines demanded by federal guidelines.
Stone will serve two years' probation after his custodial sentence. He has also been fined $20,000 (£15,500) and must serve 250 hours of community service. He will not have to report to prison until Judge Jackson rules on a pending defence motion for a new trial, based on a claim of juror bias.
As Judge Jackson handed down the sentence, she seemed to allude to Mr Trump, saying Stone "was not prosecuted for standing up for the president, he was prosecuted for covering up for the president".
She continued: "The dismay and disgust at the defendant's belligerence should transcend party."
"At his core, Mr. Stone is an insecure person who craves and recklessly pursues attention."
Entering the courthouse flanked by his wife, family and friends, Stone walked past several protesters, including one giant inflatable rat dressed as Mr Trump, another demonstrator shouting "traitor".
Awaiting Stone's sentencing, Mr Trump sent a tweet that seemed to question his ally's conviction and name-checking a host of perceived enemies.
“They say Roger Stone lied to Congress.” @CNN OH, I see, but so did Comey (and he also leaked classified information, for which almost everyone, other than Crooked Hillary Clinton, goes to jail for a long time), and so did AndyRead More – Source