Updated

Former Massachusetts Sen. Scott Brown officially launched a U.S. Senate bid in New Hampshire Friday, saying he wants to "stop complaining and get involved again" in Washington.

Brown announced the bid at the first day of the two-day Northeast Republican Leadership Conference Friday, which features prospective presidential candidates and other GOP heavyweights looking to court New Hampshire voters and put their stamp on party affairs. Former Pennsylvania Sen. Rick Santorum, a 2012 presidential candidate, and Louisiana Gov. Bobby Jindal headlined Friday's speaking program.

Brown said his wife told him he should run for the U.S. Senate in New Hampshire if he really wants to make a difference.

"Honey, you are right," he said. "I'm going to stop complaining and get involved again."

Brown's announcement of a Senate campaign against New Hampshire's first-term Democratic Sen. Jeanne Shaheen may overshadow the weekend event in Nashua.

Brown has begun seeking campaign staff while aggressively courting New Hampshire elected officials and key GOP activists in recent weeks. At the same time, his camp has begun offering paid positions to Republican operatives for a prospective New Hampshire campaign.

The longtime Massachusetts resident recently relocated to his seacoast New Hampshire vacation home. An exploratory committee would officially allow him to begin raising money and hiring staff.

Brown shocked the political world and rose to national prominence by winning the 2010 special election to replace the late Massachusetts Sen. Ted Kennedy, but he was soundly defeated in his first re-election test against Sen. Elizabeth Warren in 2012.

He had worked as a paid contributor for Fox News, but that contract has since been ended.

"Scott Brown's contributor agreement was officially terminated today once he notified FOX News of his intention to form an exploratory committee to run for U.S. Senate in New Hampshire," Fox News Executive Vice President for Programming Bill Shine said in a statement.

Several people involved in the discussions about Brown's future said some in the GOP establishment remain skeptical, given the former Republican senator's recent track record. Brown, 54, angered Massachusetts Republicans last year after indicating he would run in the state's special U.S. Senate election, only to change his mind late in the process.

"He's been reaching out to opinion leaders, to grass-roots activists, getting a sense of, `Would you be supporting a Scott Brown campaign?"' said former New Hampshire Rep. Frank Guinta, who is running again for Congress and was included in Brown's outreach efforts. "That, to me, says he's serious. But I think only Scott Brown knows if Scott Brown is going to run."

Democrats scoffed at a prospective Brown candidacy, noting that he is also considering a 2016 presidential campaign. An adviser confirmed Friday morning that Brown has canceled plans to visit Iowa next month.

"Scott Brown is for Scott Brown and the powerful interests that back him, not New Hampshire," said Harrell Kirstein, spokesman for the state Democratic Party. "So when he gets back from his next trip to Iowa, he'll find himself in a tough Republican primary against Republicans who are actually from New Hampshire. If he survives that, he'll face an even tougher general election against Jeanne Shaheen."

Shaheen, a former governor, was widely expected to win her first re-election test in November before Brown began hinting late last year that he might cross state lines to challenge her. National Democrats already have their hands full defending more vulnerable Democratic incumbents across the country as they fight to retain their six-seat Senate majority.

While recent polls give Shaheen a solid lead in a prospective matchup, Brown's near-universal name recognition in a state that shares a media market with Massachusetts and his national fundraising network would make him a serious contender should he enter the race.

The Associated Press contributed to this report.