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Jerry Brown, left, is sworn in as the 39th governor of California by California Chief Justice Tani Cantil-Sakauye, right, as Brown's wife, Anne Gust-Brown, center, looks on Jan. 3, 2011 in Sacramento. Click to see full-size.

SACRAMENTO — Jerry Brown swept into office as the oldest governor of California on Monday, his hand on a bible that belonged to his wife’s grandfather.

The flinty Democrat pledged to solve the state’s $28 billion budget deficit and confront unemployment, crime and troubled public schools.

In his inaugural speech, Brown reiterated his commitment to slice government spending and tackle the thorny issue of spiraling pension costs — a direct challenge to the constellation of public-employee labor unions that helped bolster his shoestring campaign against former eBay chief executive Meg Whitman.

“The year ahead will require courage and sacrifice,” said Brown, 72, in an address that lasted less than 15 minutes. “In this crisis, we simply have to learn to work together as Californians first, members of a political party second.”

Brown, a Democrat who served two terms as governor from 1975 to 1983, before going on to become mayor of Oakland and, most recently, state attorney general, reiterated his campaign pledges to add “no new taxes” without voter approval and to return crucial decisions to localities and schools.

He underscored his commitment to “honestly assess” the state’s financial morass, create new jobs and devote more resources to develop new ways to generate energy.

Brown is taking office as the state faces intractable problems ranging from a squabbling state Legislature that rarely passes a budget on time to whopping pension shortfalls that threaten to swallow public services or trigger tax increases. Brown is expected to present a budget-cutting plan on Jan. 10.

“In the coming year, we will grapple with the problems of our schools, with our prisons, our water supply, its reliability, and the environment,” Brown said. “We will also have to look at our system of pensions and to ensure that they are transparent and actuarially sound and fair — fair to the workers and fair to the taxpayers.”

Aides to Brown said the new governor took pains to infuse his trademark thrift into Monday’s swearing-in ceremony and inauguration party in Sacramento.

The swearing-in event at the Sacramento Memorial Auditorium — across the street from the upscale loft Brown shares with his wife, Anne Gust-Brown — was packed with campaign loyalists and dignitaries including former House Speaker Nancy Pelosi, U.S. Sen. Dianne Feinstein, Lt. Gov.-elect Gavin Newsom and former Gov. Gray Davis. It featured a spirited performance by the choir from the Oakland School for the Arts, a charter school that Brown founded and considers one of his signature achievements. The late-afternoon inaugural celebration is an invitation-only affair planned at the state-owned California State Railroad Museum in Old Sacramento. Brown’s immediate predecessor, Arnold Schwarzenegger, once appeared at the museum during the 2003 recall campaign and promised to curb the influence of special interests in Sacramento.

The inaugural events are budgeted to cost less than $100,000, collected from donors who contributed up to $5,000 each, said Steven Glazer, an advisor to Brown, who added that the administration would release a donor list in the coming weeks.

Brown’s understated approach on the first day of his third term in office portends a no-frills leadership style, Glazer said.

“It will be a straightforward approach without a lot of bells and whistles,” Glazer said.

Brown took the oath, flanked by his wife, Gust-Brown, pausing for effect as he wryly repeated a key phrase that he would take office with “no mental reservation.”

“No mental reservation whatsoever,” Brown echoed slowly, as the crowd roared its approval.