Jon M. Huntsman Jr. opened his day on Tuesday by formally declaring his candidacy for the Republican presidential nomination. He closed it by accomplishing an equally important task: collecting $1.2 million for his campaign.

A dinner in Manhattan, hosted by Lynn Forester de Rothschild, was the venue to kickoff Mr. Huntsman’s fund-raising effort. It was the first stop in a weeklong fund-raising sprint, as Mr. Huntsman tries to catch up with the rest of the Republican presidential field that is locked in a cutthroat scramble to sign up high-dollar donors.

Mr. Huntsman is attending a fund-raising dinner Wednesday night in Columbia, S.C., followed by three finance events Thursday in Florida. By Friday, he will be in Utah, where he will raise money on the same day that Mitt Romney, his Republican rival, will visit the state.

Mr. Romney is expected to have raised more money than any other Republican candidate when the second-quarter deadline arrives on June 30, but Mr. Huntsman is aggressively working to post a strong showing from the final 10 days of the month.

When Mr. Huntsman returned to the United States seven weeks ago from serving as ambassador to China, his campaign-in-waiting included a long list of potential contributors for him to meet. He and his wife, Mary Kaye, have spent considerable time meeting those donors, including Ms. de Rothschild, a longtime Democratic supporter of Hillary Rodham Clinton who changed party loyalties in 2008 and endorsed the Republican ticket.

Mr. Huntsman has attracted a boldface list of Republican donors to his campaign, including two diplomats from the Bush administration: Julie Finley, ambassador to the Organization for Security and Cooperation in Europe, and David F. Girard-diCarlo, ambassador to Austria. He also has signed up Phil Knight, chairman of Nike; William E. Ford, chairman of the General Atlantic investment firm; and Howard Berkowitz, chief executive officer of the BlackRock investment company.