LIVINGSTON — With his boisterous, sometimes brash and classically Jersey political style, Gov. Chris Christie on Tuesday finally announced his bid for the presidency, declaring he is "ready to fight for the people" of America.

A relaxed Christie — with his wife, Mary Pat, and four children standing next to him — spoke freely and blamed both parties for gridlock in Washington, and said straight talk and "strong leadership and decisiveness" would relieve weary voters.

"I am now ready to fight for the people of the United States of America," Christie, 52, told a crowd of about 1,000 in the old gymnasium of his alma mater, Livingston High School, during an unscripted speech unlike any other kickoff this year.

The two-term governor and former federal prosecutor, who three years ago was a burgeoning GOP star, enters the most crowded field in recent history and with far less shine, having since endured scandal, a sputtering economy and sagging polls.

MORE: What people are saying about Christie's 2016 run

Yet Christie, a political brawler born in Newark to a Sicilian mother and Irish father, used the 30-minute speech to reintroduce himself as a teller of hard truths who follows his heart and who can offer more than made-for-YouTube moments.

"As a candidate for president, I want to promise you a few things," Christie said. "First, a campaign without spin, or without pandering or focus group-tested answers. You're going to get what I think, whether you like it or not, and whether it makes you cringe every once in a while or not."

His mother, Sandy, whose dying words were, "Nothing's left unsaid between us," informs his public service, he said, telling the crowd that voters deserve to know where he stands on issues if they are going to trust him to fix the country.

"I don't seek the presidency for any other reason than I believe in my heart that I am ready to work with you to restore America to its rightful place in the world, and to restore the American dream to each one of our children," Christie said.

In declaring his campaign at Livingston High, Christie returned to the place of his last presidency — in 1980 as head of his graduating class. If elected, he would be the first New Jerseyan to occupy the White House since Woodrow Wilson left in 1921.

The scene was part political convention, part championship football game, without elaborate decoration so as to focus every last ounce of attention on Christie. Outside, hundreds of teachers, environmentalists and Hurricane Sandy victims chanted in protest, "Hey hey, ho ho, Christie for president. ... Hell no!"

The campaign will be Christie's toughest and most high-stakes to date, pitting him against more than a dozen other candidates, including cash-rich Gov. Jeb Bush, whose brother, former president George W. Bush, kick started Christie's career.

Now, his campaign for president will boom or bust in New Hampshire, where for the next five days he will tout what he considers his biggest achievements as governor of a majority Democratic state, including bipartisan changes to the state's teacher tenure law and public employee pension and health benefits.

Should Christie gain in the polls, however, his rivals will have plenty of material to hurl at him, starting with the criminal charges against a former senior aide and two other allies, one of which pleaded guilty, in the George Washington Bridge scandal.

Though Christie has not been directly implicated in the 2013 lane closings at the bridge and he has denied involvement, the charges tarnished an administration he once bragged about for not having a "hint of scandal or criminal activity."

He will also face questions about the state's nine credit downgrades on his watch, the most of any New Jersey governor, as well as his conduct as U.S. attorney and other issues that led Romney to decide he was too risky to join the ticket.

Christopher Baxter may be reached at cbaxter@njadvancemedia.com. Follow him on Twitter @cbaxter1. Find NJ.com Politics on Facebook.