Marissa was somewhat of an outcast at school. She was once paired up with her school jock, Matt Eding, who continuously stalked her, sending her notes and calling to ask her out, despite the fact that he already had a girlfriend. She then told the guidance counselor about it, which in turn got him benched for a week. His girlfriend, Natalie Kent, found out and started taking out her anger on Marissa.
After sometime, Marissa and her friend Laurie jokingly cast a spell to summon the demon of hatred, Hete, but a wrong mix of potions made the demon turn against her instead. She began an internship at The Bay Mirror, where Phoebe had a premonition. Coincidentally, and Leo was assigned to by the Elders to look after the girl. The sisters realized what had gone wrong and attempted to banish the demon, but accidentally worsened the situation when the demon escaped and infected the entire town. When the students at Marissa's school started attacking her, she made her way to the Halliwell Manor. The sisters drew Hete out from the angry mob and then banished him, leaving everyone infected confused. Marissa continued her internship with newfound confidence.
- That she was able to cast a spell and be assigned to Leo's protection suggests that she was either a witch or a practitioner. However, Leo only stated that she was 'a rebel with a cause.'
Marissa Hargrave has appeared in a total of 1 non-canonical novel throughout the franchise.