LOS ANGELES — When Jerry Brown became governor of California again, three years ago, this state was on a steep decline, crushed by budget deficits, deep spending cuts, governmental paralysis, high unemployment and a collapsing housing market. California, a place that once symbolized promise and opportunity, seemed caught in an intractable reversal of fortune.

But these days, Mr. Brown — who at 75 is the oldest governor in the nation and about to become the longest-serving governor in the history of California — is enjoying a degree of success and authority he and his opponents could scarcely have imagined when he returned to Sacramento to begin a second tour as governor in 2010.

The state’s budget problems are largely resolved, at least for the short term. Mr. Brown is the dominant figure in Sacramento, strengthened by overwhelming Democratic control of the Legislature and the decline of the Republican Party. He has pushed through major initiatives on education financing and prison reorganization. Even Republicans say his re-election next year seems considerably more than likely.

“Some people were ridiculing California, and some were calling it a failed state,” Mr. Brown, a Democrat, said in an interview. “The unemployment came down from 12.2 to 8.5. Real estate is rebounding. There’s a lot of confidence out there. That’s what happened.”