At 7:35 this morning, with a helicopter circling overhead and her presidential grant of clemency in one hand, Patricia Campbell Hearst walked our of federal prison, almost five years to the day after the now-legendary kidnaping that ultimately put her in.

She wore a blue down jacket, beige slacks, and the broad, open smile that had become increasingly familiar as publicity mounted in the national drive to commute her seven-year sentence for robbing a bank in 1974. Bernard Shaw, her 33-year-old finance, walked by her side. She looked clam, well fed, and thoroughly happy.

"I want to see my parents," Hearst said. "And my sisters... I'm really happy to be going home."

She spoke into the dark bouquet of microphones just outside the prison fence, her voice very soft, and at one point held high over her head the clemency order signed last Monday by President Carter. "Here it is," she said, still smiling.

The president accepted the Justice Department's conclusion -- reached after a nine-month national clemency drive by the 24-year-old heiress' friends and well-wishers -- that Hearst's punishment had already been substantial, that her kidnaping led to her criminal activity, and that her rehabilitation was complete.

A low-slung rope and a folding table separated Hearst from the reporters and photographers, who descended today on the Pleasanton prison (some arriving long before daybreak) in such numbers that three military guards were directing traffic and a special bank of 20 pay telephones had been set up on the lawn. They formed a protective barrier, this rope and table, a fence against the shouting preporters who had pursued Hearst, pushing each other and waving microphones, into the prison when she began doing time at Pleasanton last May 15. Hearst had taken one look at the press that afternoon and had broken into a dead run, a terrified young woman literally chased inside the heavy front gate of a federal prison.

But that almost desperate public fascination has followed Patricia Hearst for five years now, ever since the violent night in February 1974 when she was dragged from her apartment into the unlighted streets of Berkeley, screaming, "Not me! Oh please, not me!"

She was an heiress to the empire of, William Randolph Hearst, a newspaperman of extraordinary power who had lived in a castle with zebras and a movie star; she was young; she was physically small; she jarred memories of the kidnaping of the Lindberghs' baby. And after the first "communique" arrived, a tape delivered anonymously to Berkeley radio station KPFA, anybody who watched television or read a newspaper knew that Patricia Campbell Hearst had been taken "prisoner of war" by a leftist organization called the Symbionese Liberation Army.

But beginning with her startling appearance on a film made secretly during the April 15, 1974 holdup of a San Francisco branch of Hibernia bank came the next 19 months -- the one wo had vowed to "stay and fight." Patricia Hearst -- known by now through her tapes as "Tania," the name of a guerrilla who died alongside revolutionary Che Guevara -- had stood to one side with an automatic rifle in her hands while other SLA members stole $10,680. A month later she appeared in Los Angeles with SLA members William and Emily Harris and sprayed a sporting goods store with rifle fire. Her voice, often sounding scornful, still came through the SLA tapes: "Death to the fascist insect that preys upon the life of the people."

After the May 17, 1974, house fire and gun battle with police in which six SLA members died, she vanished, as far as the FBI was concerned. It is believed she and the Harrises fled to the East Coast and then worked their way back West -- and despite an intensive nationwide police search, Patricia Hearst was not found again until September 1975, when she, the Harrises and another fugitive named Wendy Yoshimura were arrested in the Latin neighborhood of San Francisco.

Hearst was charged with participating in the Hibernia bank robbery. As she was photographed during her capture, she clenched one fist, raising it in defiant salute, and as the enormously publicized federal trial got underway, it was this image, this smiling and cocky young woman with the tight fist, that stirred the most basic arguments.

Had she taken up this life voluntarily? Had the SLA's apparently brutal initial treatment of Patricia Hearst -- she had been kept blindfolded in a closet for a week, she said, taunted about how her family had deserted her, and sexually abused -- proved so traumatic that Hearst was no longer capable of acting independently? Had she been brainwashed?

Patricia Hearst -- by now sober, genteel, with fist noticeably unclenched -- insisted throughout the trial that she had been forced into the Tania role, and that she lived in constant fear. The jury apparently did not believe her. She was found guilty on March 20, 1976, and after being released on $1 million bail was sentenced to seven years in prison.

She now wears a green rhinestone medallion bearing the word "survivor" and the date of her kidnaping, and soon to include the date of her release. It had been reported that her fiance would gieve her a bulletproof vest to wear if she walked our of prison, but Hearst said she had not put it on. "But I dressed for the occasion," she said, and showed off a green T-shirt emblazoned with the words, "Pardon Me."

"I think I've become a lot stronger, a lot more self-confident," Hearst said later this morning, from her mother's home in Hillsborough (her parents are separated), where she was taken for what she said was her most immediate wish -- breakfast with the family -- before leaving on vacation to an undisclosed place. "I take a lot of things in stricde that make other people fall apart," she said.

Shaw, a San Francisco police officer who met Hearst when he began moonlighting as her security guard while she was out on bail, said they have decided to marry in April, on a military base, where the security will be tight.

Is she planning to do some writing? "It looks as though I'm going to have to," said Hearst. How she could travel without being recognized as Patricia Hearst? "I don't see anything wrong with being Patricia Hearst," she said and her friends sitting nearby burst into applause.