It's a peculiarity in the film roles of Gloria Grahame that she was so often more memorable than the people who were meant to be the memorable ones.
Take, for instance, The Bold and the Beautiful. It's supposed to be Lana Turner's film - She's the "Beautiful" of the title, after all, but somehow Grahame's doomed housewife sticks with me more. Or how about The Big Heat? The image of Lee Marvin throwing hot coffee in her face is the most memorable in the film, but her role as the superficial, fragile Debby is a vital linkage between Glenn Ford's psycho cop and Marvin's thug.
Grahame and Film Noir were a natural fit. She wasn't cool and beautiful in the Turner or Veronica Lake mould, but embodied a sexy throw-me-down-on-the-linoleum quality that that type couldn't quite manage.
Grahame's career at the top was relatively short, but her resume is impressive indeed. Check her out in Crossfire, In a Lonely Place, Macao, Human Desire (again with Ford), and Man on a Tightrope.