Trump tweeted Sunday morning in a series of posts attacking Corker that he denied the senator's request for an endorsement -- a claim denied by Corker's chief of staff, Todd Womack, later in the day.
"The president called Senator Corker on Monday afternoon and asked him to reconsider his decision not to seek reelection and reaffirmed that he would have endorsed him, as he has said many times," Womack said in a statement.
Trump told Corker he was going to endorse him the day the Tennessee Republican announced his intention to retire, two sources familiar with the discussions said.
Corker, whose term expires at the end of next year, made the announcement that he would retire late last month.
Trump's slams on Corker come days after the senator made public comments criticizing him. The senator responded to Trump's tweets with an insult later in the morning, calling the White House "an adult day care center" in a Twitter post.
And he wasn't done there.
In remarks to The New York Times published on Sunday night, Corker said Trump was treating the presidency like "a reality show," making reckless threats against other countries that put the United States "on the path to World War III."
Corker also said Trump acts "like he's doing 'The Apprentice' or something," and that alarmed the senator, according to the Times.
"He concerns me," Corker told the newspaper. "He would have to concern anyone who cares about our nation."
And the risks Trump's behavior presents also concern some of his top officials, who endeavor daily to protect the President from his own instincts, the Times reported.
"I know for a fact that every single day at the White House, it's a situation of trying to contain him," Corker told the newspaper.
The flare-up between the two leaders highlights the long-simmering differences between GOP leaders and the President, who has not shied away from attacking the leadership over their inability to move health care legislation.
It also comes as Trump prepares to press Congress to advance his proposed tax overhaul and tensions reportedly grow between Trump and members of his own Cabinet -- especially Secretary of State Rex Tillerson -- on issues such as the way to handle North Korea's nuclear weapons program.
Corker's vote will be critical on tax reform, and he remains an influential voice on Trump's foreign policy challenges, including over how to handle the Iran nuclear deal.
It's not the first time Trump and the White House have privately sent one signal to Corker while publicly saying something else.
Following Corker's pointed attack on Trump for his handling of the deadly violence in Charlottesville, Virginia, in August, Vice President Mike Pence quietly sought to repair ties with Corker after the President knocked the Tennessee Republican on Twitter, sources said.
On Sunday morning, Trump again launched an attack on Corker.
"Senator Bob Corker 'begged' me to endorse him for re-election in Tennessee. I said 'NO' and he dropped out (said he could not win without..." Trump tweeted.
"..my endorsement). He also wanted to be Secretary of State, I said "NO THANKS." He is also largely responsible for the horrendous Iran Deal!"
"...Hence, I would fully expect Corker to be a negative voice and stand in the way of our great agenda. Didn't have the guts to run!" Trump added.