Scott Brown's big day.

Now the official Republican nominee for U.S. Senate, Scott Brown wasted no time in getting his campaign off to a roaring start.

Beginning with his election night speech, in which he told supporters, "Whatever the usual insiders and experts have to say about this election, I say this: Never underestimate the independent spirit of Massachusetts," Brown has launched what promises to be an aggressive underdog campaign.

"I don't have all the advantages in this race, and that's fine by me.  I don't come from a life of advantage, and in many ways I'm grateful for that," Brown said on Tuesday night, acknowledging the difficult race ahead of him. He added, "The political machine in this state is going to pull out all the stops to keep their hands on this Senate seat. Rest assured it will be me against the machine."

Yesterday, with his tremendous victory barely 12 hours behind him, Brown quickly went on the offensive against his Democratic opponent, Martha Coakley.

Brown signed the Americans for Tax Reform (ATR) Taxpayer Protection Pledge, a promise not to raise taxes on the American people, and immediately challenged Coakley to do the same.

“When I first ran for state office, I signed a pledge not to raise taxes. Today, as a candidate for U.S. Senate, I am renewing that pledge. Very simply, I will not raise taxes on the American people,” said Brown. “President Kennedy had it right when he said years ago that every dollar released from taxation will help to create a new job and a new salary. Raising taxes kills jobs and hurts our economic recovery.”

He added: “Voters have an opportunity to send a powerful message to the tax-and-spenders in Washington that they can’t continue on with business as usual. We can start by making it clear that higher taxes are not an option. I challenge my opponent in this race to renounce her support for higher taxes and to take the no-tax pledge.”

The tax pledge reads:

“I, Scott Brown, pledge to the taxpayers of Massachusetts, and to the American people that I will: ONE, oppose any and all efforts to increase the marginal income tax rates for individuals and/or businesses; and TWO, oppose any net reduction or elimination of deductions and credits, unless matched dollar for dollar by further reducing tax rates.”

Brown then continued his whirlwind first post-primary day by launching his "Jobs are Job One" tour with a visit to Universal Plastics in Holyoke.

According to a Brown campaign press release, Universal Plastics is a manufacturing business that supplies a range of products to the aerospace, electronics and medical industries. Since employing a high of 88 people in January 2008, the bad economy has forced Universal Plastics to lay off nearly half its workforce as the two-year national recession has dragged on and orders have fallen. The company now employs 50 workers.

“Good jobs were lost here and we can get them back by lowering the tax burden on businesses,” said Brown. “It’s no secret that lower taxes lead to job growth and as U.S. Senator I will fight to keep taxes down so that companies like Universal Plastics can increase their sales and hire more people.”

Brown said that at a top marginal rate of 39 percent, the United States is tied with Japan for the highest corporate tax rate in the world. If elected to the U.S. Senate Brown said he would fight to reduce this rate to help companies become more competitive and add more jobs.

Today at 2:00 p.m., Brown will continue his jobs tour at the Polar Beverages factory in Worcester.  He will join Jim Braude on NECN's Broadside tonight at six, and then will get some national pub when he joins Neil Cavuto on the Fox Business network at 6:40 to discuss the economy.

It appears Scott Brown isn't going to stop working until January 19.