But what was billed as a day of elegant campaign events at the homes of the ultrarich turned out to be an afternoon of curious and clashing tableaus: protesters with their bandannas and Occupy Wall Street-inspired chants (“We got sold out, banks got bailed out!”) standing amid multimillion-dollar mansions, where live bands played “Margaritaville” and donors dined on prosciutto-wrapped melon balls.

A luncheon fund-raiser was held at the sprawling home of Ronald O. Perelman, the billionaire financier and Revlon chairman. Widely described as the largest estate in East Hampton, when last advertised in the early 1990s, the house was said to have 40 rooms, 9 fireplaces and a mile of frontage on Georgica Pond.

After that, Mr. Romney attended events at the Southampton homes of Clifford Sobel, the former United States ambassador to Brazil, and David Koch, the billionaire industrialist and longtime benefactor of conservative political causes.

Mr. Romney, who amassed a fortune as a private equity executive, seemed sensitive to the imagery of the presumptive Republican nominee spending a day raising money in some of the most exclusive corners of the Hamptons. In remarks to about 250 donors inside a giant white tent on Mr. Sobel’s property, Mr. Romney pointedly acknowledged the financial comfort of those around him.

“If you are here, by and large, you are doing just fine,” he said, his voice audible to a reporter standing on a public street not far away. “I don’t spend a lot of time worrying about those here. I spend a lot of time worrying about those that are poor and those in the middle class that are finding it hard to make a bright future for themselves.”