Arias, now 34, managed to avoid the death penalty for the 2008 murder of her ex-boyfriend, a Mormon motivational speaker named Travis Alexander.
In an unusual move, Arias testified in her own defense. She admitted killing Alexander but said he was an abusive pedophile who attacked her first.
During the trial, Arias' lawyers acknowledged that she killed Alexander but claimed it was self-defense. Her lawyers presented one psychologist who diagnosed her with post-traumatic stress disorder (PTSD). That PTSD, her defense argued, made her forget stabbing Alexander or cleaning up his blood. Here's what we know about Arias' life before the gruesome murder trial.
An 'Almost Ideal' Childhood
She was born in Salinas, California and went to Yreka Union High School, where she was a "good girl" who didn't seem the slight bit off, her close high school friend Tina Ross told HLN TV.
She grew up with both of her parents, four siblings, and grandparents who lived nearby. She told the TV show "48 Hours" that her childhood was "almost ideal," ABC reported.
Arias, an aspiring photographer, dropped out of high school in the 11th grade, though.
During her 20s, she worked a series of dead-end jobs and cycled through relationships with cheating boyfriends, she told jurors in the Arizona courtroom where she was tried, according to the AP.
She eventually got a job with a company now known as LegalShield, which pays its "work from home" sales force on commission.
It was through this work that she met the man she'd kill. They got together at a 2006 conference in Las Vegas for Prepaid Legal Services, as it was then known.
A Complicated Relationship
At the time, Arias was living in Palm Desert, California, and Alexander was in Mesa, Arizona, but the two struck up a long-distance relationship. They exchanged 82,000 emails, according to court records cited by The Huffington Post.
Alexander told his friends that Arias hacked into his Facebook account and slashed his tires after they broke up, according to multiple news sources.
"She (Arias) was, like, totally obsessed with Travis," Alexander's friend Julie Christopher told CBS 5.
'A Walking Embodiment Of Sociopathy'
Crime expert Scott Bonn told HuffPost's Dave Lohr that Arias is a textbook sociopath.
Sociopaths have something "severely wrong" with their consciences, according to "Psychology Today," and Arias remained mostly composed during her televised murder trial.
"She is really a walking embodiment of sociopathy in many ways," Bonn told HuffPost. "The ironic thing about that, I believe, is that is part of the intrigue. There's a disconnect: How can this pretty young woman be responsible for this reprehensible, incomprehensible act?"
Arias' belief that she could convince a jury that she stabbed Alexander nearly 30 times to defend herself also reflects a classic sociopathic trait: narcissism.
Arias initially told investigators she knew nothing about Alexander's murder, and then blamed it on masked intruders before finally claiming self-defense.
"This self-defense position that she is taking is the third in a series of realities that she's created, none of which is consistent with the other," Bonn told HuffPost. "It's consistent with a sociopath personality. She's so narcissistic and enamored with herself that she thinks she can make it believable."