Updated at 3:10 p.m. ET:
Brown took his oath for a third term as governor of the nation's most populous state. He's no longer the "Gov. Moonbeam" of my youth. The 72-year-old has been hailed by the Los Angeles Times as "a stolid party leader" and "senior statesman of Sacramento."
He called on Californians to help the state overcome a $28 billion budget shortfall.
"The people of California have not lost their pioneering spirit or their capacity to meet life's challenges," said Brown, who was once the state's youngest governor and is now its oldest.
The Democrat, who has been on the state and national stage since the 1970s, defeated former eBay chief executive Meg Whitman, who spent a record $141 million on her campaign. He is one of eight governors in the U.S. mainland who will be sworn in today.
In keeping with Brown's populist bent, the new governor's inaugural party will feature hot dogs and chips at the state Capitol. Brown first served as California governor from 1975 to 1983.
Schwarzenegger, the body builder-turned-actor-turned Republican "Governator," was first elected in 2003 and presided over some of California's toughest financial times. Brown will inherit a $28 billion budget shortfall.
In one of his last official acts, Schwarzenegger reduced the prison sentence of a son of a former speaker of the California Assembly. Esteban Nunez, now 21, was serving a 16-year sentence for his role in the slaying of Luis Santos.
Schwarzenegger said he reduced Nunez's prison term to seven years because Nunez did not deliver the fatal knife blow to Santos' heart.
Political observers say Brown must set the right tone in his inaugural address and ease voter concerns about the state's yawning budget deficit. As Mark Baldassare, president of the Public Policy Institute of California, told the Sacramento Bee, Brown has to be upbeat.
"People are looking for hope and confidence to come out of that speech," Baldassare said. "Something that would be difficult for people to handle right now, I think, would be a sense of doom and gloom."
(Posted by Catalina Camia)
Catalina Camia leads the OnPolitics online community and has been at USA TODAY since 2005. She has been a reporter or editor covering politics and Congress for two decades, including stints at The Dallas Morning News and Congressional Quarterly. Follow her at @USATOnPolitics.