"Let Jeb be Jeb" was the message Bush's advisers conveyed.
A former Florida governor, Bush will launch his campaign for the November 2016 election in Miami on Monday, having built a well-funded organization but facing some of the same dilemmas that Romney faced.
Opinion polls show the 62-year-old Bush tied for the lead with others in a packed field of Republicans hoping to succeed President Barack Obama. Obama's former secretary of state, Hillary Clinton, leads the pack among Democrats.
In 2012, having failed to define himself otherwise, Romney left himself open to attack from rivals in both parties. Democrats called him an out-of-touch wealthy elitist. Conservatives were skeptical of him.
Like Romney, Bush faces an uphill task persuading conservatives in the Republican Party that he is one of them. He will also want to avoid being branded inaccessible.
"The prime thing he talks about is he wants to go about showing his heart," said Bush spokesman Tim Miller, recalling the message of exit polls on Election Day in 2012.
"A lot of people highlighted in the exit polls how Mitt Romney beat Obama in a lot of characteristics but was trounced when it came to 'who cares about people like me,'" Miller said.
In a secretly recorded video in 2012, Romney famously portrayed Obama's supporters - which he said were 47 percent of the electorate - as people who live off government handouts and do not "care for their lives."
It was only when a sympathetic documentary came out in 2014, long after he lost to Obama, that Americans saw a different side of Romney. The "MITT" movie was packed with behind-the-scenes video of his family life, including his pain at losing the election.
A STARK DIFFERENCE
North Carolina donor Theresa Kostrzewa, who raised campaign dollars for Romney and now donates to Bush, attended Bush's April retreat in Miami. She saw a stark difference between the two campaign organizations.
"We learned who the real Mitt was two years after the election when someone did a documentary," Kostrzewa said. "The mantra of this campaign is, 'Let Jeb be Jeb.'"
"Let Jeb be Jeb" means Americans will see Bush in places Romney did not visit and where candidates of their white-dominated party don't always go, such as black churches, Hispanic neighborhoods and college campuses, a Bush adviser said.
Where Romney was tightly controlled, Bush will make a deliberate attempt to be more accessible to voters, taking their questions at town hall-style events, a far less-scripted pattern than that practiced by Romney.
And where Romney had few interactions with reporters who covered him, occasionally tossing fast-food hamburgers to them on his plane but infrequently taking their questions, Bush has appeared largely comfortable sparring with the media, despite a stumble over whether he would, like his brother President George W. Bush, have launched the Iraq war knowing what he knows now.
Significantly, advisers said, Bush will work to define himself in a way that respects his famous family but stresses an independent path, like his formative years spent in Venezuela. And he will show people that he cares by stressing his record as Florida governor, they say.
Bush and his advisers may not dwell on the Romney example - they say it does not come up in meetings - but they are aware of the lessons learned.
Bush adviser Sally Bradshaw co-authored an official autopsy report on the 2012 election that found, "we have lost the ability to be persuasive with, or welcoming to, those who do not agree with us on every issue."
By sticking to his moderate positions on immigration and Common Core education policy, Bush is trying to prod Republicans into being more inclusive, a risk given the rightward tilt of the party in recent years.
"I am going to be who I am, I am not going to change who i am because at a given point in time someone has a particular point of view," Bush told reporters in Estonia on Saturday as he concluded a three-nation trip.
Should he win the nomination, his positions could help him in the general election campaign when the nominees of both parties will be reaching for the undecided voters in the middle of the political spectrum.
For now, though, Bush is open to attacks from Republican rivals who will try to outflank him on the right and feed on conservative fears that he is not one of them.
Bush, whose Right to Rise SuperPac is raising perhaps $100 million for starters, will be prepared to fight back, a stance underscored by Bush's hiring of pugnacious Republican political veteran Danny Diaz as his campaign manager.
As proof that Romney remains a looming presence and potential power broker, the former Massachusetts governor played host this weekend to several Republican candidates at a donors' retreat in Deer Valley, Utah. He had breakfast on Friday with Bush rival Marco Rubio, a Florida senator.
Ron Kaufman, a senior adviser to Romney in 2012 who is backing Bush, said Bush and his team will need to work hard to define their candidate and stress his conservative record as governor of Florida from 1999 to 2007.
"Once Americans are reminded, shown and discover the depth of his leadership as governor and the things he accomplished, I think his numbers will rise," Kaufman said.