But, after Trump spent months making baseless claims that election fraud cost him the November election against Democrat Joe Biden, McConnell said that overturning the vote because of objections from the losing side would see American democracy enter "a death spiral".
After that vote, McConnell ripped Trump in a speech from the Senate floor, and the two have been estranged in recent months after working closely together during the former President's four years in office. House Minority Leader Kevin McCarthy also visited with Trump at Mar-a-Lago a few weeks ago and most House Republicans - with the notable exception of GOP conference chair Liz Cheney - view Trump as a force in the party.
In a vicious attack laced with ingratitude, Trump accused Senate Minority Leader Mitch McConnell of "lack of political insight, wisdom, skill, and personality", just days after Senate Republicans- under McConnell's leadership - thwarted Democrats' effort to convict him on the impeachment charge that he incited the deadly January 6 Capitol riot.
The statement did not include any sign of contrition from Mr Trump for his remarks to a crowd of supporters who then attacked the US Capitol on Jan 6.
Minutes after the Senate voted Saturday, the Senate's longest-serving Republican leader said Trump's actions surrounding the attack on Congress were "a disgraceful, disgraceful dereliction of duty". However, he voted later that day to acquit the former USA president on the single impeachment charge of "incitement of insurrection".
A spokesperson for McConnell did not immediately return requests for comment.
While speaking with Fox News hosts Harris Faulkner and Bill Hemmer about the passing of conservative radio personality Rush Limbaugh on Wednesday, Trump answered questions about the late radio personality's take on the 2020 U.S. presidential election, once again insisting that he had "won" on November 3.
He also said McConnell "begged" for his endorsement in the senator's home state of Kentucky while running for re-election previous year - and suggested he would work to defeat McConnell and his Republican allies, saying he planned to "back primary rivals who espouse Making America Great".
In private, he has said he believed the impeachment proceedings would make it easier for Republicans to eventually purge Mr Trump from the party. However, he defended Trump on the narrow grounds that impeachment should only apply to sitting presidents.
One person close to Mr Trump said his initial version of the statement was more incendiary than what was released publicly.
In the statement, he resorted to insults about Mr McConnell's acumen and political abilities, and faulted him for the Republicans' loss of their Senate majority.
Josh Holmes, McConnell's former chief of staff, told the Post that he would be "very surprised" if McConnell "ever says the words Donald Trump again".
"Without my endorsement, McConnell would have lost, and lost badly".