Usagi was a bit selfish and very much a crybaby, and was lazy, clumsy, and an academic underachiever. She was also a terrible cook, as shown several times during the series. She could be jealous and possessive of Mamoru, as shown in episode 136. However, it was shown that she cared very deeply for her friends and family.

She was very trusting, and believed that everyone had a better nature; this could be both a character strength and a character flaw at times. She did not believe in killing innocent humans, even when they had been transformed into vicious monsters, and always sought ways to heal them instead.

Over the course of the series, Usagi matured a great deal, and even though she was still prone to some childish behavior and bouts of silliness, she became a capable young woman.