The current attorney general has emerged as the Democrat's presumed candidate in 2010 with just seven months to go to the primary.
The 72-year-old politician finds himself in that position after the field of contenders exited in the face of a stealth fundraising campaign and his near universal name recognition.
It's not the spot in which the majority party in a state as diverse as California had expected to be in, just a year after a grassroots groundswell helped give Barack Obama the biggest margin of victory in a California presidential election since at least World War II.
The seeming inevitability of Brown's candidacy has left some Democrats nervous about what his campaign might produce. He is famously independent, often unpredictable and his views are not as well known as his name to many of today's voters. He has also mostly stayed out of the debate about the state's massive fiscal crisis.
"There's a whole generation who have no idea who he is, and there's a lot of activists who have no clue on how he'd balance the budget because he hasn't articulated it," said Steve Maviglio, a Sacramento-based Democratic consultant. "That's why there's a level of nervousness about Jerry Brown being our only choice."
The Democratic Party and California's electorate have grown increasingly diverse in the years since Brown last served as governor 26 years ago. The party's legislative caucus is relatively young and is dominated by Hispanics, blacks and Asians.
During his tenure from 1975-1983, and some of his ideas were considered wacky enough to earn him the nickname "Governor Moonbeam." He was also known for dating starlets and singers.
But some Brown initiatives had lasting effects, including his opening of government to women and minorities and deals with public employee unions. The famously combative Brown also sought the Democratic presidential nomination in 1976, 1980 and 1992.
Another unknown is how Brown would fare against a deep-pocketed Republican such as Meg Whitman, the former chief executive of eBay, who is a fresh face on the political scene and is aggressively targeting women voters.
The Democrats' unexpected position heading into the 2010 governor's race prompted a lament from former Assembly Speaker Willie Brown, who wrote in his weekly newspaper column that some Democrats are asking: "Can't we find someone with a newer paint job?"
Brown is likely to claim that what's old is new again, invoking ideas that he first championed as governor, including environmental protection, high-speed rail and fixing California's schools, all of which are once again on California's agenda.
Brown's seven-to-one fundraising advantage and 20-point lead in public opinion polls forced San Francisco Mayor Gavin Newsom out of the race last month. Newsom, 42, who was best known for approving same-sex marriages in his famously liberal hometown, was the favorite among younger Democrats.
Another concern is that Brown has not officially announced his candidacy and has not detailed his views on critical topics, although he has signaled he will oppose tax increases.
Steven Glazer, a political adviser to Brown, said Brown will have time for politics later.
"I'm very confident he will make a decision to run, but he's focused on doing his job as attorney general right now," Glazer said.
In a statement released by Glazer, Brown seemed to indicate that releasing detailed proposals about how to allocate California's dwindling resources, as some Republicans have done, does not demonstrate how the candidates would solve the budget crisis.
"The first step in (the budget) process is forming a working consensus among key Democratic and Republican leaders. Unless that is achieved, protracted stalemate will continue to be the order of the day," Brown said.
U.S. Sen. Dianne Feinstein is the only Democrat thought to have enough name recognition and financing to challenge Brown.
Feinstein, 76, toyed with the idea this week in an interview with The Associated Press, saying she is waiting to see what proposals the candidates offer to address California's ongoing budget shortfalls before she decides whether to run.
Without Brown in the race, 2010 might have been a dramatic year with a diverse field of Democratic candidates a generation or more younger than he is, including Newsom, Rep. Loretta Sanchez of Santa Ana and Los Angeles Mayor Antonio Villaraigosa. Brown's expected run scared off many of the would-be challengers early.
The worries about Brown as a candidate, given his famously erratic personality and propensity for outlandish statements, have mostly been muted so far because Democrats covet the governor's office after six years under Republican Gov. Arnold Schwarzenegger.
If Brown emerges as the nominee, Democratic strategists will rally around him, banking on his proven ability to win statewide races.
"Overriding all of (it) is a real thirst among Dems to win back the (governor's office), almost at any cost," Maviglio said.