The billionaire had called the news conference to announce an accounting of his at least $5.6 million in fundraising for veterans groups, but spent most of the 40 minutes criticizing and insulting reporters -- collectively and at times individually -- as "dishonest," "not good people," sleazy, and among the worst human beings he has ever met.
And he vowed the White House briefing room would be just as combative as the Trump Tower lobby, where the developer addressed reporters Tuesday, should he ascend to the Oval Office.
"Yeah, it is going to be like this," Trump said when asked if this is how he would behave with the press as president. "You think I'm gonna change? I'm not gonna change."
At one point, Trump fumed: "I'm the only one in the world who can raise almost $6 million for the veterans, have uniform applause by the veterans groups, and end up being criticized by press."
"I think the political press is among the most dishonest people that I have ever met, I have to tell you. I see the stories, and I see the way they're couched," he added.
The news conference did not mark a radical departure from Trump's relationship with the press, which has been strained throughout the brash mogul's year-long campaign -- but Tuesday was a surprise escalation, especially at a time when many supporters want him to start acting more presidential.
Over the last year, Trump has repeatedly called out individual reporters on Twitter and in interviews for everything from what he viewed as insufficient crowd camera shots to biased reporting. And attacking the press is a regular part of the presumptive Republican nominee's stump speech, during which he typically rips reporters as "scum," "slime," "dishonest" and "disgusting" — often prompting jeers from the crowd.
The news conference came four months after Trump claimed to have raised $6 million for veterans groups, but then dodged reporters' questions about which groups had received the donations.
Trump kicked off his litany of media attacks Tuesday by accusing reporters of cynically turning what should have been a positive story about his charitable work into a negative one.
Reporters had for months repeatedly asked Trump to provide an accounting of the donations, requests that were frequently rebuffed or side-stepped by Trump and his campaign staff.
Trump said Tuesday he didn't "want the credit" for his fundraising, "but I shouldn't be lambasted."
Hillary Clinton later told CNN's Jake Tapper on "The Lead" that Trump did not deserve any credit for following through on his promise, arguing that he had only done so because of increased scrutiny of the donations from the media.
"Look, I'm glad he finally did it, but I don't know that he should get much credit," she told Tapper. "It took a reporter to shame him into actually making his contribution."
The subject of the news conference quickly turned away from the veterans donations as Trump accused reporters of writing stories they "know" to be false, and of spinning the truth.
He lashed out at individual reporters, calling ABC's Tom Llamas a "sleaze," referring sarcastically to CNN's Jim Acosta's live reports as a "beauty," and refusing at one point to call on CBS's Major Garrett.
Trump repeatedly blasted the media for the way it has covered his fundraising for vets.
"All of the money has been paid out," Trump said. "The press should be ashamed of themselves, and on behalf of the veterans, the press should be ashamed of themselves."
"There are so many people who are so thankful for what we did," Trump said, adding that the final figure could top $6 million once all the donations are in.
Trump listed the vets groups -- there were more than 40 -- that he said had received money and the amounts given to each. He said there were no administrative costs deducted from the donations.
Trump himself gave $1 million last week to the Marine Corps-Law Enforcement Foundation, a charity that helps support the families of fallen Marines and law enforcement officers to which Trump's foundation has previously donated.
Amid reporters' questions over the last few months, Trump and his campaign have repeatedly offered conflicting accounts of how much money was raised. The campaign has insisted it was working on disbursing the funds, but said it was waiting on some donors to make good on their pledges and also needed time to properly vet the charities in the running to receive the funds.
Three veterans groups earlier Tuesday confirmed donations from the Trump Foundation. The Bob Woodruff Foundation and the Boston Wounded Vets Run each got $75,000. The Racing For Heroes Foundation also received what the group's president described as a "large" donation.
Clinton's campaign on Tuesday morning fired off a statement tweaking Trump over his accounting of the donations amid a multi-pronged push to counter Trump's news conference.
And Clinton herself clashed with Trump's description on Tuesday that she had done "nothing" on veterans' behalf, pointing to money she raised for the Intrepid Fallen Heroes Fund alongside Arizona Sen. John McCain and work done to re-acclimate veterans returning from combat.
She said "of course" she had contributed personally as well. But she didn't provide further details, such as how much she donated and to whom.