After a failed first bid in 2008, a shift toward more conservative positions, victory in this year's Republican primaries and then a tack back to the center, Romney can finally see the ultimate prize within his grasp.
With just days to go before the biggest night of his political life, Romney is in a dead heat with President Barack Obama.
Should he win, he would make history as America's first Mormon president.
A loss would likely bring an end to a political career that began with a failed 1994 Senate run but saw Romney go on to become the governor of Massachusetts and eventually the flagbearer of his Republican Party.
The management skills and determination that made him so effective in business as he amassed a huge fortune and saved the Salt Lake City Olympics from ruin are fine White House credentials.
But Romney, 65, has struggled to counter the image that congealed in the primaries battle and beyond -- that of a policy flip-flopper with awkward social skills, a Mormon faith that he is reluctant to discuss, and questionable concern for America's struggling lower classes.
Is he a cut-throat venture capitalist or a skilled manager with the business acumen to turn around the American economy? A cunning political chameleon or a constantly recalculating fake with secret liberal leanings?
Romney is a difficult character to pin down and staunch conservatives harbor concerns that he really shares their views on hot-button issues such as gay marriage and abortion.
Throughout the roller-coaster primaries, rivals struggled to land telling blows on the former Boston venture capitalist who managed to stay above the fray while giving off the air of an inevitable nominee.
Despite lingering doubts, he handily won the nod of his party as the candidate with the best chance of beating Obama.
Early in the campaign the multimillionaire businessman demonstrated a tin ear with a string of wealth-related gaffes -- including challenging Republican Governor Rick Perry to a $10,000 bet during a debate -- that made it all too easy for opponents to portray him as out of touch with ordinary Americans.
Romney's image received a carefully scripted makeover at the convention in Tampa, Florida, as he tried close the yawning likability gap between himself and Obama.
Wife Ann invoked their love story as high school sweethearts to show the human side of a man whose ram-rod straight bearing is lampooned as too stiff, and whose hair is clearly too perfect.
The couple's squeaky-clean and loving family life -- they have been married 43 years and have five sons and 19 grandchildren -- is a clear vote-winner.
Mitt was born into wealth and privilege in Detroit in 1947, the son of George Romney, who served as Michigan governor and chairman of American Motors.
George Romney tried and failed in his own presidential bid, briefly emerging as a top contender for the 1968 Republican nomination before losing to Richard Nixon.
His son was often at his side while campaigning for the governorship, but for two years his Mormon faith took Mitt to France as a religious missionary.
It was there in 1968 that tragedy struck. Romney had been driving members of the Mormon church when another car slammed into their Citroen. A passenger in Romney's car was killed, and Romney himself nearly died.
But he recovered and returned to the United States and to Ann, whom he married months later.
As a rising star with a Harvard degree in law and business, he joined Bain & Company in 1977, where he so impressed the chief executive that in 1984 he was entrusted to head the new venture capital arm, Bain Capital.
Romney ran the firm for 15 years, earning spectacular wealth and laying the groundwork for a political career that from the beginning seemed geared toward the national stage.
During his 2003-2007 governorship of Massachusetts, he built a reputation as a moderate deal-maker and he allied with Democratic state lawmakers to gave birth to the nation's first universal healthcare program.
After losing the 2008 nomination to Senator John McCain, he has subsequently distanced himself from his crowning gubernatorial achievement as the program served as a model for the nationwide plan created by Obama in 2010, which most Republicans despise.
This fits seamlessly into the narrative perpetuated by White House attack ads -- that Romney has undertaken a wholesale reversal of many positions for political gain.
Initially "pro-choice," Romney switched to become anti-abortion after being elected governor. He made a similar about-face on gay rights.
He raised eyebrows among conservatives when he said in early October that he could not foresee supporting any new law restricting women's rights to abortion, but rowed back the next day, pledging to be a "pro-life president."
Romney faced opprobrium for comments that surfaced in August in a video that showed him disparaging "47 percent" of voters as government-beholden victims.
The remarks threatened to do him in, until his command performance in his first debate with a lackluster Obama, in early October.
He came out of the showdown a clear winner, and polls soon show him running neck-and-neck with the incumbent.
