Gloria is the deuteragonist in Happy Feet. She is the love interest of Mumble in the first film, in which she is voiced by the late Brittany Murphy, and his mate in the second, in which her voice actress is replaced by pop singer P!nk.
Gloria and Mumble were best friends as chicks. In fact, Gloria watched Mumble's egg and gave him that name. Gloria stood up for Mumble, when other penguins teased him that he was a bad singer and that an icicle fell on his head from that. In return, Mumble developed feelings for her.
When they got older, Mumble still had those feelings for her, but then, more men began fighting for her attention. Gloria seemed to still care for Mumble, though it didn't seem like she actually had romantic feelings for him. For instance, when Mumble starts singing off key, she kindly tells him to stop, unlike everyone else who started screaming at him.
When it came time for Gloria to find her mate, she began singing, looking for her him (as is the tradition for penguins according to this movie). Suddenly, she sees Mumble, who is singing very well for once, and it seems that she finally found her soul mate. However, she soon realizes he is not actually singing, but is just lip-syncking. Mumble starts stomping his feet, which Gloria starts singing to, and they get happy that they may be meant for each other after all. However, they emperors don't approve of them being together this way, and banish Mumble.
Mumble is eventually met up with Gloria, who tells him that she loves him, and wants to be his mate, but Mumble tells her that its not safe for them to be together.
However, after Mumble saves the entire penguin population from starving, he is accepted back to his home, and he and Gloria marry and have a child.