Katharine Hepburn won the Oscar for playing Eva Lovelace in Morning Glory.
Morning Glory is just an average film, that works well if Katharine Hepburn works well. The story is interesting, it's well made, but the supporting cast seem a little out of place and searching for something to do. It's all about Katharine Hepburn, and rightfully so.
It is true - Hepburn overacts here. But, that doesn't mean it's bad or unfitting, because Eva is always trying to bring attention to herself. It's very theatrical, and purposely so. Kate adds so much dominating charm to the character of Eva, she lights up the screen. Eva's personality is so perfectly realized by Hepburn, that when we see the weakness show throw her fascinated facade, we feel a deep sympathy for her.
It's definitely a divisive performance, and I've been in that front of that criticizing line, but now I appreciate the work on display by Katharine Hepburn.