Lord Black of Crossharbour, former proprietor of the Daily Telegraph and a number of other world newspapers, served more than three years in prison after being convicted of fraud and obstruction of justice in 2007.
Mr Trump rang the 74-year-old Canadian-born British citizen to inform him of the pardon last week, with the president saying it would “expunge the bad wrap you got”.
The pair have previously described each other as friends, with Mr Trump calling Lord Black “one of the truly great intellects and my friend” and said he “won’t forget” after the publication of an article in the National Enquirer – titled Trump Is The Good Guy – about his campaign.
In response to the December 2015 tweet, Lord Black wrote: “Many thanks, Donald and all good wishes in helping to clean up the American government. Honored to be your friend.”
Lord Black, born in Montreal, Canada, was the former head of Hollinger International, which once owned the Daily Telegraph, Chicago Sun-Times, Jerusalem Post and hundreds of community papers in the US and Canada.
He was ennobled as Lord Black of Crossharbour in 2001, having renounced his Canadian citizenship to become a Conservative peer.
His downfall came in 2007 when jurors in Chicago found him and other Hollinger International executives swindled shareholders out of more than six million dollars (then worth around £3 million) of their money.
Writing in Canada’s National Post on Thursday, Lord Black spoke of the phone call in which Mr Trump gave him the news.
“He could not have been more gracious and quickly got to his point: he was granting me a full pardon that would ‘Expunge the bad wrap you got’.
“The American criminal justice system is frequently and largely evil; I was convicted for attempted obstruction of injustice. It was never anything but a smear job.”
A jury found Lord Black illegally received 3.5 million dollars (£1.75 million) as they convicted him of three counts of fraud and one of obstruction at the Dirksen Federal Courthouse in Chicago, Illinois.
He was cleared of a further six counts of fraud, with the jury of nine women and three men clearing him of charges of racketeering and tax evasion.
The jury had to consider 42 counts against him and his three co-defendants – John Boultbee, of Victoria, British Columbia, Canada, and Peter Atkinson, of Oakville, Ontario, who are both former Hollinger International vice presidents, and former corporate counsel Mark Kipnis, of Northbrook, Illinois – in a highly complex trial.
The prosecution said the money came mainly from the sale of hundreds of Hollinger-owned US and Canadian regional newspapers between 1998 and 2001, in which the buyers paid large sums in return for agreements that Hollinger would not compete with the new owners.
Lord Black was granted bail pending an appeal against his conviction in 2010, with two of the fraud counts against him overturned in October of that year.
In a statement, the White House said: “In 2007, prosecutors alleged that Lord Black had committed several acts of mail fraud and obstruction.
“The Supreme Court of the United States, however, largely disagreed and overturned almost all charges in his case. He nevertheless spent 3.5 years in prison.”
White House press secretary Sarah Sanders said Lord Black “has made tremendous contributions to business, and to political and historical thought”, adding that high-profile individuals — including Henry Kissinger, Elton John and Rush Limbaugh — had “vigorously vouched for his exceptional character.”