Scott Brown officially launched his campaign for U.S. Senate in New Hampshire on Thursday, WGBH-TV reported.

"I want you all to know about a decision I've made," he told the crowd in Portsmouth. "Starting today, I am a candidate for the United States Senate for the state of New Hampshire."

In his speech, the GOP candidate railed against his likely opponent -- Democratic incumbent U.S. Sen. Jean Shaheen -- for supporting Obamacare.

"So many problems with our country and the economy happened, and continue to happen, because of everything that's related to Obamacare," he said. "And you need to remember - it's so critically important that you remember - that this never would have happened without the rubber-stamp yes vote of Sen. Shaheen."

Brown is not new to the political scene, as he was a U.S. senator in Massachusetts a few years ago before being beat out by U.S. Sen. Elizabeth Warren. Though he hasn't recently lived in New Hampshire for too long, he stressed to the crowd that his family originated in their state.

"When my mom was young, she was a waitress at Hampton Beach," he said. "And my dad was an airman at Pease Air Force base, and they met, they fell in love, and about a year later they had me. And I'll tell you, when they carried me home, it wasn't too far from here. It was a house right over on Islington Street."

Recent polls demonstrate Brown trailing behind Shaheen, according to WGBH.

In December, Brown mistook New Hampshire for Massachusetts during a visit with a local Republican group.

"What I've heard from the Republicans up here is they're thankful that I've been around for a year helping them raise money, helping them raise awareness as to the issues that are affecting not only people here in Massachusetts - I mean New Hampshire - but also in Massachusetts obviously, and Maine," Scott said, according to video released by the Democratic super-PAC American Bridge.