Trump arrived at Verst Logistics in Hebron, Kentucky as part of a trip touting his affordability agenda.
In rambling remarks that focused heavily on last year's GOP tax and spending bill and attacks on Democrats ahead of the midterms, the president singled out Massie — who has emerged as a leading GOP critic of his own party's spending, military strikes overseas, and the piecemeal release of the Epstein files.
Trump repeatedly resorted to name-calling, and dubbed Massie "Rand Paul, Jr." in a reference to his recent breaks with the party.
"We've got to get rid of this loser," Trump said. "This guy is bad. He's disloyal to the Republican Party, he's disloyal to the people of Kentucky, and most importantly he is disloyal to the United States of America."
Massie did not immediately respond on social media, but the congressman has said the president and his allies are spending millions to unseat him in an attempt to keep his fellow Republican House members in line.
Kentucky Democrats said in a statement that Trump "can't sell his failing economy to Kentuckians struggling to buy groceries and gas."
On Iran and energy, the president again offered up mixed messages, cheered the decision by the International Energy Agency member countries to release 400 million barrels of oil, "which will substantially reduce the oil prices as we end this threat to America and this threat to the world."
While celebrating the attacks on Iran, saying, "They don't know what the hell hit them," Trump again suggested the U.S. doesn't want to "leave early" and must "finish the job."
Statewide Republican officeholders were in attendance, including Attorney General Russell Coleman, Auditor Allison Ball, Sec. of State Michael Adams, and Treasurer Mark Metcalf.
U.S. Senate hopefuls Andy Barr, Daniel Cameron, and Nate Morris — all of whom are vying for the president's endorsement — were in the audience.
Trump also brought media influencer Jake Paul and former Covington Catholic High School student Nicholas Sandmann to the podium.