Charlie Baker takes over as 72d governor of Mass.

Charles Duane Baker Jr., a Beacon Hill budget whiz turned health insurance chief executive and politician, was sworn in today as the 72d governor of the Commonwealth of Massachusetts.

Surrounded by legislators, dignitaries, and supporters, and amid the pageantry of taking an office first held by John Hancock, the 58-year-old Republican placed his left hand on a family Bible, raised his right and took the oath.

Baker assumes the reins of power from outgoing Governor Deval Patrick, returning the Corner Office to Republican control for the first time in eight years.

But Baker, speaking to an overwhelmingly Democratic Legislature, offered a broadly inclusive speech, quoting John F. Kennedy and referencing a Roxbury youth program and a Lowell teen center, alongside pledges to simplify and streamline state government and hold the line on taxes.

Baker lauded those areas where the state leads, from biotechnology to health care reform. But he made veiled knocks at Patrick’s tenure, saying some of the state’s toughest challenges “have been ignored, perhaps lost amid the successes. Or have become the equivalent of kicking a can down the road because they’re not politically convenient or easy to fix.”

He also spoke about an urgent state budget gap, that outside analysts have pegged at about $1 billion, though Patrick aides strongly dispute that number.

“History will record that a budget deficit exceeding half a billion dollars is being transferred to our administration,” he said, addressing the legislators he will almost certainly need to work with to find cuts to help bridge the gap.

“If we’re honest with ourselves, we can’t blame this deficit on a lack of revenue. We have to recognize that this is a spending problem,” he said. “And that dealing with it now will make balancing next year’s budget that much easier.”

As Baker was speaking about the budget gap, a man in the chamber yelled, “Blame it on the former governor!” Baker did not acknowledge the outburst.

The new governor also referenced some management failures during Patrick’s term, including the bungled roll-out of the state’s health insurance website after it was changed to comply with the federal health care overhaul.

“We will challenge the status quo,” he said.

Baker offered full-throated support for an expansion of charter schools in the state, which are taxpayer-funded but operate outside of local control and tend not to be unionized.

“While traditional public schools will always be the backbone of our education system, we need more high-performing public charter schools,” he said.

Baker gave his address after the pomp and circumstance of the official swearing-in ceremony for him, Lieutenant Governor Karyn Polito, and the Governor’s Council, a colonial-era body that approves judicial appointments and pardons.

Later Thursday afternoon, he is set to take a tour of the Dudley Street Neighborhood Initiative in Boston, meeting with community leaders and elected officials.

Then Baker is scheduled to attend a big inaugural reception and celebration at the main South Boston convention center, featuring musical groups from across Massachusetts.

Before his inauguration, Baker arrived at the more than 200-year-old golden-domed capitol building amid pomp and circumstance. He shook hands on Beacon Street, before walking up the main State House the steps with his wife, three children, and Polito and her family.

Baker stood at attention as a 19-gun salute was fired by the 54th Massachusetts Volunteer Regiment National Guard and then entered the building, where he was greeted by throngs of supporters, many wielding cell phone cameras and wide smiles.

Legislators began to fill the chamber of the House of Representatives in the 11-o’clock hour. And not long before noon, former governors Mitt Romney and William F. Weld, former US senator Scott Brown, and New Jersey Governor Chris Christie and Rhode Island Governor Gina Raimondo mingled near the front of the historic room.

Baker’s ascension marks a shift of more than just party.

An outsider, Patrick rose to his first elective office in 2006 with soaring rhetoric and a transformative vision, but he sometimes struggled to turn that vision to reality, knocking up against the ingrained ways of Beacon Hill. And, in recent years, Patrick has faced management failures in state government.

Baker’s speaking style is plain. He campaigned on broad themes such as a crafting a stronger economy and better schools, using the bland slogan: “Let’s be great, Massachusetts.” But he arrived in the chamber of the House of Representatives to take the oath today intimately familiar with the State House.

After college, he served in communications roles for the New England Council and the Massachusetts High Technology Council, a business lobby. A few years later, he helped direct the Pioneer Institute, a conservative think tank, and was then hired into the administration of newly elected governor William F. Weld, who took office in 1991.

Baker, seen as a wunderkind in the administration, rocketed from undersecretary to secretary of health and human services, and then became the most powerful Cabinet member: the state’s budget and administration chief, who leads the charge on crafting billions of dollars in spending.

Baker later went on to be chief executive of Harvard Pilgrim Health Care, helping to lead it from the brink of financial catastrophe to a nationally recognized success.

But when he made his first bid for governor in 2010, attempting to harness the antigovernment zeitgeist of the year with the bitter slogan, “Had enough?” he fell short in his effort to unseat Patrick.

Trying for the Corner Office again last year, Baker was more upbeat on the campaign trail and offered a bipartisan — almost nonpartisan — message that often focused on making government more effective for citizens, and underscored his management expertise.

Those skills will now be put to the test.