Instead of being joined by their wives, which was the original expectation, Republican National Committee Chairman Reince Priebus was their only other guest. He was tapped by Trump to become his chief of staff when he enters the White House in January.
The three men ordered a young garlic soup with thyme and sautéed frog legs, and diver scallops with caramelized cauliflower and caper-raisin emulsion as appetizers, according to a readout to reporters.
Priebus and Trump ordered a prime sirloin with citrus glazed carrots for their main course and Romney ordered lamb chops with a mushroom bolognese sauce. All three of the men had a chocolate cake for dessert.
CNN asked Trump after the dinner if Romney will be the next secretary of state, to which he responded, "Well, we're going to see what happens."
And Romney addressed reporters in the lobby about the dinner, where he said he had a "wonderful evening" with Trump.
"We had another discussion about affairs throughout the world and these discussions I have had with him have been enlightening and interesting and engaging. I have enjoyed them very, very much," he said.
He added: "By the way, it's not easy winning. I know that myself. He did something I tried to do and was unsuccessful in accomplishing. He won the general election. And he continues with a message of inclusion and bringing people together and his vision is something which obviously connected with the American people in a very powerful way."
Despite their rocky past, Trump and Romney didn't show any animosity whatsoever between each other, as servers dressed in neckties and vests carried out their duties. The three men appeared animated and smiling, as seen by a CNN reporter also in the dining room.
The fight between Romney, the Republican Party's 2012 nominee, and Trump was nasty and personal.
After Romney said he didn't expect Trump to win the GOP nomination and called some of the real estate mogul's past comments "childish in some respects," Trump tweeted: ".@MittRomney can only speak negatively about my presidential chances because I have been openly hard on his terrible "choke" loss to Obama!"
Trump fired back, saying that he could have forced Romney to his knees in 2012 when Romney sought his endorsement.
"He was begging for my endorsement. I could have said, 'Mitt, drop to your knees' -- he would have dropped to his knees," Trump said.
Romney's speech sparked a furious back-and-forth that only ended after the election when, in a stunning turn, the two met
to discuss Romney becoming secretary of state. Since that meeting, conservative backers of Trump have been openly bashing Romney, including former Arkansas Gov. Mike Huckabee and former House Speaker Newt Gingrich.
On Sunday, Priebus downplayed any fighting behind the scenes, suggesting that picking Romney would make for a good "team of rivals" for Trump.
"He's going to be making the best decision for the American people. It isn't a matter of warfare. I mean, there's a lot of opinions about this and, yes, it is sort of a 'team of rivals' concept if you were to go towards the Gov. Romney concept," Priebus said on "Fox News Sunday."
Romney has also stirred up emotions among Trump aides. Kellyanne Conway, a top Trump adviser, first opened a window on the infighting in Trump's transition over who should win the powerful role as the nation's top diplomat, when she tweeted on Thanksgiving about concerns with Romney
"Receiving deluge of social media & private comms re: Romney Some Trump loyalists warn against Romney as sec of state," she tweeted, including a link to a Politico story.
Romney has been scrapping behind the scenes with Rudy Giuliani for the post, although alternative options have emerged, including former Gen. David Petraeus and Tennessee Sen. Bob Corker.
Conway told CNN's Dana Bash Sunday on "State of the Union" that much of the anger, which has boiled over in public, stems from the personal attacks Romney lobbed at him.
"There was the Never Trump movement and then there was Mitt Romney he gave speeches against Donald Trump, he attacked his character," Conway said.
A source in Trump's campaign told CNN that Trump was "irritated" with Conway's public campaign against Romney's potential nomination for the position.