In the salad days of his administration, California Gov. Edmund G. (Jerry) Brown Jr. was quick to celebrate the virtues of what he called "creative inaction."

The mystic telegenic governor was seen by his admirers as the political equivalent of Muhammad Ali, who in his younger days boasted that he could float like a butterfly and sting like a bee. Brown's critics said that he simply was not a leader.

"He called it creative inaction," former Assembly speaker Bob Moretti once complained about Brown. "I call it sitting on his ass."

All that has changed now. In the week and a half since the passage of Proposition 13, the Jarvis-Gann property tax initiative. Brown has confounded both his friends and his adversaries with a performance of crisis leadership that has rarely been equaled in state government.

In an atmosphere of near panic caused by the threat of massive service cutbacks and job layoffs in California cities, counties and school districts. Brown has moved forcefully to demonstrate that the tax limitation he has long opposed could be made to work.

The day after Proposition 13 passed, Brown clamped a hiring freeze on state government. He followed this up with proposals that junked many of his highly hallyhooed programs, such as a California space satellite. He froze the salary of all state workers.

At week's end, dozens of specific budget cuts proposed by the governor had been in corporated by the legislature into the pending state budget in line with Brown's goal of imposing a percentage cut on state spending similar to the cuts required of local government under Jarvis-Gann.

Brown's argument, generally accepted even by Republicans who otherwise oppose him, is that the suffering should be shared. Voters want spending cutbacks on all levels, said Brown, and reducing state spending will free money to help the local governments and schools that were the direct targets of the initiative.

Brown has scored media triumphs before.The most persistent critism of him has been thta he lives for such victories and rarely backs up his symbolic triumphs with acts of substance.

This, too, has changed. In an effort to make sure that his legislation is as good as his rhetoric, Brown has brought in Ed Hamilton, a highly regarded budget analyst during the John V. Lindsay administration in New York and a one-time "whiz kid" for former secretary of defense Robert McNamara.

The staff work and the quality of the complex legislation that is needed to carry out the various fund transfers to local government have been so good that a legislative aide accustomed to sloppy work from administration technicians was moved to exclaim: "They're actually doing what they said they were going to do."

For Brown, the crisis has been heady wine. He has told intimates that his political future depends upon what happens in Sacramento before the July 1 deadline imposed by Proposition 13. Brown sees the changes now occurring here as the biggest shift in political direction since the New Deal, and he is keenly aware that the rest of the nation is watching California.

Beyond that, Brown seems to be enjoying himself. His demeanor is confident, his answers crisp and cool, his relations with the legislature more businesslike and professional than in the past.

Though some think Brown has been undermined by Democratic Assembly Speaker Leo McCarthy, who tends to understate the magnitude of the $5-billion-plus state surplus, the governor goes out of his way to praise McCarthy publicly. Where he once tried to make public points by scorning the politicians of the legislature, Brown now pays the homage to their egos that is the traditional price of legislation.

One person close to the governor thinks Brown was bored by his job before Proposition 13 and is excited by it now.

"Jerry loves a crisis, and sometimes went out of his way to created one," says this intimate. "Now Howard Jarvis has created a crisis for all of California, and Jerry's in his element."

The change has been good and even necessary politics, of course. Republican state Attorney General Evelle Younger, who has been vacationing in Hawaii while Brown struggles with Jarvis-Gann, ran a good gubernatorial primary campaign, and is viewed as a strong challenger to Brown in November's general election.

Since Younger supported Proposition 13 while Brown opposed it, the governor would be an odds-on favorite to lose the election if he emerges from the current crisis as a weak, ineffective leader. But Brown and his aides believe that the opposite is also true.

"I think it's one of the great opportunities that anyone in state government, maybe even national government, has ever been afforded," says Brown's executive secretary, Richard Silberman.

There are others in the Brown entourage who agree with Silberman but say that more than political advantage is at stake.

"In some ways," says Brown's legal counsel, J. Anthony Kline. "Jerry sees what has happened as a gift. He has always resented the accusation that he's all symbol and no substance. This gives him a chance to lay that myth to rest.I think he's going to do it."