Misa is a famous model, singer and actress and is infatuated with Light Yagami. She usually refers to herself in the third person by calling herself "Misa-Misa" to be cute and tends to be hyperactive. Though Misa wears jewelry with a crucifix theme in the manga, she wears fleur de lis jewelry in the anime adaptation (however, the cross is retained on the collector's figure included with Volume 5 of the DVD series). Despite her hyperactivity; she rarely, if ever, allows her personal feelings about anyone to interfere with Light's plans, showing her unflinching loyalty to him. She, like Light, is corrupted by the power that comes with owning a Death Note. However, unlike Light, she neither wishes to become a god, nor loses her original personality.
Douglas Wolk of Salon describes Misa as being drawn in a "Japanese comics' tradition of cute, tiny, airhead girls with big eyes" and being a "lot cannier than she pretends to be." Wolk adds that the reader could "watch her measuring how much quasi-innocent charm to pour on in every situation."
She decides to devote her life to Light because he punished the criminal that killed her parents when she was younger; a burglar killed Misa's parents in front of her eyes. Misa, unable to forgive the killer and wanting to kill the burglar herself, saw multiple delays in the killer's trial before Kira killed him. According to Ohba, Light sees Misa as a "bad person" who killed innocent people, so he acts emotionally cold towards her and manipulates her. She understands that Light does not truly love her, but as she states during her first meeting, she does not care that she is just being used. Light and Misa both act together as Kira for over five years, until Light decides that it is too dangerous for Misa to be Kira with members of the taskforce suspecting him.
Not only is Misa grateful to Light, but she has been emotionally damaged by the loss of her parents. She feels that if Light does not love her, than she can at least pretend that he does. She has openly expressed her desire to be loved ("I want to be loved!") and wants to give Light everything she has so that he may eventually reciprocate her feelings.
The Shinigami who follows her is Rem. Not long before Misa's introduction to the series, Misa was attacked by an obsessed stalker. Unbeknowst to her, a Shinigami named Jealous had fallen in love with her, and was watching her during the attack. In order to save her life, Jealous wrote her stalker's name into his notebook, killing him. Consequently, Jealous himself died, since Shinigami exist only to take human life, not extend it. Rem, who witnessed the whole event, then took Jealous' notebook which had been left behind, and gave it to Misa, and the two eventually grew to care for each other. Misa also performs two eye trades, cutting her lifespan in half twice; the first was with Rem, and the second with Ryuk. However, two shinigami destroyed themselves for her (Jealous and Rem), which added their remaining, undetermined, years to hers.
According to 13: How to Read, Misa loses her memories related to using the Death Note and retains her love for Light. Since it is in the nature of a Death Note user to "suffer misfortune", Misa falls into despair after someone "like Matsuda" "probably let it slip" that Light died. Despite fan rumors, the cloaked woman who appears at the end of the manga is not Misa, but an unnamed follower of Kira. Misa's fate is not shown in the manga at all; she was last seen staying at the Teito Hotel. Ohba stated that this was simply because he did not have a situation to fit her in.
At the anime's finale, Misa appears standing outside the safety rail on the edge of a skyscraper looking into the sunset dressed in Gothic Lolita clothing (which incidentally happens to be the same one in episode 25 which leads the viewers to wonder whether this had been a future reference), presumably about to jump to her death.
Misa, born on December 25, 1984 in Kyoto, has a height of 152 cm and a mass of 36 kilograms (79 pounds). Misa has a bust size of 76 centimeters, a waist size of 51 centimeters, and a hip size of 75 centimeters. Her blood type is AB. (see Blood types in Japanese popular culture)