Sculptor Jo Davidson was a star chaser. With an autograph collector's enthusiastic greed he went after the Big Names.

He portrayed them by the hundreds, he used clay and he worked fast. Before he died at 69 in 1952, he "busted" Tito, F.D.R., Einstein, Mussolini, Gandhi, Arthur Conan Doyle, Charlie Chaplin, Lindbergh, James Joyce, Shaw, Gide, Pershing, Helen Keller, Will Rogers, Andrew Mellon, John D. Rockefeller, Ike, Ben-Gurion Stein. The list goes on and on.

He viewed his portraits of celebrities as "a plastic history" of his time.

He must have been a charmer. His beard was black and bushy, his eyes were said to dance. He did not pose his sitters; he sought movement, animation. On those rare occasions when he worked from photographs, he used movie films, not stills.

"I wasn't thinking in terms of sculpture as such," he wrote in his autobiography. "What interested me was the people themselves - to be with them, to hear them speak, to watch their faces change." He flattered them, he courted them, he liked to make them laugh.

The National Portrait Gallery (which is about to celebrate its 10th anniversay) owns 42 Jo Davidsons. Of these, 25 are a recent gift from Dr. Maury Leibowitz. A little first-floor gallery devoted to the sculptor opened there last week.

The faces in the room are famous and familiar - here is Gertrude Stein, a meditative buddha; Ernie Pyle looking sensitive and doomed, and wealthy Andrew Mellon, cunning and austere. But the exhibit as a whole seems peculiarly anonymous. Davidson, the protraitist, has a personality that seeps into the walls.

His style does not startle. Unlike Brancusi, David Smith, Picasso or Matisse his sculpture does not stretch the limits of the art. His style is traditional, virile, academic. He sought a likeness, not high finish. In his portraits one still sees the thumb prints he did not smooth out of the clay.

Portraiture in sculpture is less in fashion now than it was in 1900, or in ancient Rome. Photography has helped dent its popularity as has the attention given abstract art. But the portraits of Jo Davidson are not about to be forgotten. They are tied to too much history. And his modesty protests him. His sculpture does not posture. He is, we see at once, a trustworthy reporter who could see in faces the flicker of the soul.

He would return from a sitting full of information. "He had conversations to report, and such conversations," wrote his friend Lincoln Steffens. "Hemingway would have asked to write them. They were the expression in words of the character and drama he had thumbed into clay."

His work is more direct than that of Avedon or Karsh, whose ego-ridden photographs, no matter what the subject, insist "me, me, me." Jo Davidson let his sitters do the talking.

When he'd finish sculpturing Gertrude Stein in 1923, she circled her portrait. She said, "That's Gertrude Stein, that's all of Gertrude Stein, that's all of Gertrude Stein there is."

"I was an artist, and an artist just didn't stay in his studio and work - he had to talk. Talking was part of it," wrote Davidson.He talked with Joseph Conrad, Frank Harris, Aldous Huxley; and while he talked he worked. He sang arias with James Joyce, who was afraid of thunder, and he joked with Gandhi. "I see," said Gandhi, "you make heroes out of mud." "And sometimes vice versa," Davidson replied.

The sculptor spoke of ghosts with Sir Arthur Conan Doyle, who looked more like Dr. Watson than like Sherlock Holmes. "The other day," said Doyle, while Davidson was working, "I was sitting in that very chair and my son, who has been dead for some years, came over and kissed me on the brow, something he never did in his life."

Ernie Pyle posed in a New York hotel room amid "bourbon and tobacco fumes" in 1942. Pyle in a few days, would return to the front. "I'm going simply because there is war on and I'm part of it," the correspondent said to Davidson. "I've got to - and I hate it." He went off and was killed.

Davidson was born to Russian immigrants on New York's Lower East Side in 1883. He changed his name from Joe to Jo because he did not want the other kids to call him Joe-eee. He began to sculpt while studying medicine at Yale in 1904. "The cool wet stuff gave me a thrill I had never before experienced," he wrote. "I found the clay bin, put my hand in it and touched the beginning of my life."

Though he spent much of it in France. Davidson retained a kind of New York brashness. As a young man he had hustled. He worked as a delivery boy, he decorated leather. At the World's Fair in St. Louis he "pushed rolling chairs, told fortunes, and acted as a ballyhoo for sideshows on the Pike." He sold portraits on the Boardwalk in Atlantic City underneath a sign that read, "Twenty-Five Cents for a Profile, Fifty Cents for a full face. No likeness, No Pay." The catching of the likeness was a skill he kept for life.

"The important thing is the rapport between the artist and the sitter," wrote Jo Davidson. It is not the sculptor but his sitters, one remembers from his show.