In a quiet tribute to Marilyn Monroe, LIFE.com presents a series of color pictures by Alfred Eisenstaedt, made at the movie legend’s Hollywood home more than 60 years ago, in the spring of 1953, when the actress was just 26. What’s perhaps most striking about these photos, especially in light of all we now know about Marilyn’s fraught and deeply sad life, is how relaxed, self-possessed and (dare we say it?) how happy she looks.

In 1953, her biggest, brightest roles—in Bus Stop, The Seven Year Itch, and the American Film Institute’s greatest American comedy of all time, Some Like It Hot—were still ahead of her, as were her unlucky marriages to Joe DiMaggio and Arthur Miller and her increasingly lonely, desperate last years. But it’s worth noting that she really does not resemble a legend, an icon or an idol in these pictures. Instead, she looks like a beautiful young woman evidently, and perhaps momentarily, at peace with herself and her place in the world.

All of that, of course, would soon change, and change for the worse.

But not yet, Eisensteadt’s portraits seem to say. Not yet.