WITH NO self-aggrandizing hoopla--and maybe that had much to do with it--actor William Holden spent the best part part of his more than 40-year Hollywood career as one of the most popular personalities inside, as well as outside, the film industry. With remarkable ease and versatility, Mr. Holden, who was found dead Monday in Santa Monica at the age of 63, had portrayed the all- American male figure--manly, romantic, tough and yet, well, nice--in dozens of different modes but always as a hero to men as well as women.

So good was his acting that moviegoers rarely noticed that he was acting; instead they would see the emotions, reactions and even insecurities of the man in the movie, not the actor in the role. Even in films of which he was less than proud--during the "rut of playing all kinds of nice-guy, meaningless roles in meaningless movies," as he once described them-- Mr. Holden nonetheless rose above scripts as a real person in the story line.

From award-winners to turkeys and comedies to tragedies, Mr. Holden gave a touch of class to any film. His best-known characters were distinctly different individuals: Joe Gillis, the ill-fated gigolo in "Sunset Boulevard," for which he won an Oscar nomination; the news executive with the collapsing personal life in "Network," for another Oscar nomination; the anti-hero, wisecracking sergeant in "Stalag 17"--and on and on from "Bridge on the River Kwai," "Love Is a Many-Splendored Thing" and "Picnic" to a roster of other ageless favorites.

Surely contributing to William Holden's genuine qualities on screen was his respectability off screen. He had no interest in the razzmatazz of Hollywood, preferring family and/or solitude, along with a little help for his friends and colleagues in his capacity as a leader of the Screen Actors Guild. "For me," he said, "acting is not an all-consuming thing, except for the moment when I am actually doing it. There is a point beyond acting, a point where living becomes important."

Mr. Holden reached both points with lasting effect.