Jimmy Carter met the press and they were his.

Mythology about a relentlessly probing national press corps aside, Carter's conquest isn't as difficult as it would seem. Presidents almost always hold the upper hand when they deal with the press in public. But Certainly not since John F. Kennedy has a President so dominated a press conference as did Carter yesterday.

It was Carter's most impressive public performance to date. He was polsed, confident and clearly in command from beginning to end. He handled the questions briskly, demonstrated a sure grasp of information and issues and maintained an easy, light air throughout.

Carter began his first presidential press conference by saying he looked forward to these "confrontations."

There was no confrontation yesterday, and no contest.

It was a Carter victory almost by default.

That may not be so monumental a feat, either, The format of these televised jumping-jack affairs is now part of presidential tradition. In the nature of the beast, the televised conference transforms the press into a clamoring pack shouting for attention and a chance to ask a quick question. The format hardly permits serious discussion of issues or provided fresh insights into a President's thinking.

Yesterday's conference, for example, ran true to form. In just 30 minutes Carter was asked 16 questions. His conference was half over before he was asked about the one subject that has demanded his greatest attentions, and his country's, these last two weeks - energy.

Nor was he subjected to the the pitiless interrogation of some of those supposed institutional powers in the press. The New YorK Times, The Washington Post, the Washington Star and other media heavyweights never got in one small questions. That's probably not of great moment, either; it might even be good for their institutional souls. A touch of humility and democracy at work.

But as with other presidential press conference the real story often lies not in what is asked and answered, but in how a President appears. By that test, Carter is proving to be a formidable presidential figure indeed.

So much has been made of Carter's rural origins, of his political outsider image, that his skills at mastering the most sophisticated electronic medium are often overlooked. Carter is no newcomer to television; he's been emplying it successfully for the past two years nationally. He wouldn't be President without it. Since his election he's had more warm-up practice with.

Last week he showed how effectively he could perform in his first "fireside chat," a study in careful casualness. Yesterday he showed how well he can handle the conventional press conference. He seemed to enjoy it. There was a twinkle in his eye throughout. He demonstrated that he understands the power of humor as a political device, and he also gave an excellent example of how best to answer a question - chose your own ground and give your own response, even if unrelated to the inquiry.

Carter plans to hold two such press conferences a month, he said yesterday. That's back to the standard of Eisenhower, Kennedy and Johnson, far more than Nixon and Ford, far fewer than Roosevelt and Truman.

On the basis of his performance so far, he should look forward to his press conferences. He has little to fear, so long as he is not trapped in the net of damaging events - a Bay of Pigs, a Vietnam, a Watergate.

If Carter evoked Kennedy yesteday, the press in part recalled some of its less auspicious performances in those days.

It was Sarah McClendon a veteran press gadfly from Texas, who had asked Kennedy an editorial in the guise of a question. She named two officials as "well-known security risks" and demanded to know what Kennedy was going to do about them.

Yesterday McClendon again commanded the floor.

She wanted to know about the "transgressions" of a government employee working on energy. "Are you keeping him on knowingly," she asked, "or you just didn't know about him?"

Kennedy had replied to her question with icy contempt. He hoped the people she named would continue to serve their country "without detriment to their characters by your question."

Carter used neither comtempt nor anger in replying.

"I didn't know about it," he said. He was smiling as he said it.