Christine is slim, on the short side, heart-shaped face, long brown hair, and would be considered pretty in a classical sense.
She is typically seen in business dress becoming of a journalist and columnist.
Christine has a strong loyalty to her father, wanting to be acknowledged by him. She even went to lengths to shoot Agent Lundy, killing him and wounding Debra Morgan, just to obscure her father as the "Trinity Killer", who has shown to not care about her one bit, by saying he'd wish she was never born. Deep down she's very lonely, wanting someone to be by her side, showing they care about her. She originally manipulates Quinn with her charm to find out the progress on the Vacation Murders Case. However, later on, she shows to care about him in other ways, wanting him to spend the night and to be referred to as his "girlfriend" so she wouldn't have to be alone. Once realizing how vacuous her existence was, (Not being considered a daughter to her father, and not being forgiven by Morgan) she commits suicide, ending her loneliness and complicity in her father's crimes. It's assumed after witnessing her father's crime 30 years ago when killing a woman in her bath tub, the episode had a big impact on her, and she used the incident to her advantage by protecting her serial-killer father to elicit the love and attention she craved from him that he refused to give.
Early LifeThough her parents were not married, Christine maintained a close relationship with her dad. At the age of 5, Christine witnessed her father committing one of his 'bathtub' ritual murders. Mitchell is able to convince her that it was a bad dream, but as an adult she comes to realize it was real after covering the Trinity killings. Throughout her life she is faithfully devoted to her father, even though he is generally cold towards her, only seeing her a couple of times a year and keeping her existence a secret from his family. Postcards found in her apartment imply Mitchell did occasionally express his love for her.
Christine met Joey Quinn at the scene of Lisa Bell's murder. She started a relationship with Quinn, often seducing classified police information out of him, including the Vacation Shootings, and the return of Frank Lundy to Miami. Her relationship with Quinn causes tension with his colleagues, but Angel is able to use her hovering to their advantage when he leaks that one of the vacation murderer suspects has an STD. Hill publishes the info, which causes a rift between the two murder suspects, leading one to shoot the other and quickly be caught after.
It is revealed late in the season that Christine is the daughter of Arthur Mitchell/Trinity, and was also the shooter of Frank Lundy and Debra Morgan. After seeing her byline on several stories about the Trinity investigation, Mitchell pays Hill a visit. Later, in a panic, she convinces her father to meet with her again. This time she confesses to him that she knows he is the Trinity Killer but still loves him, saying she shot Lundy to prevent him from catching her father. Mitchell is furious with her despite her support and tries to sever ties with her.
Debra is distrusting of Hill because of her job as a reporter, but eventually becomes more suspicious when Hill, while attempting to commiserate with Debra over Lundy's death, acknowledges a detail of the crime that was never reported. The police later find out the biological connection between Christine and Trinity and arrest her but she admits to nothing, claiming she never knew her father.
She later tries to contact her father again, but he says he wants nothing to do with her. Emotionally devastated by the abandonment of her father, after everything she had done to protect him, Christine confesses to Debra that she shot Lundy and apologizes. She begs Debra for forgiveness, but when Debra says she cannot forgive her, Hill quickly reveals a gun hidden under her seat and kills herself. Later, when Dexter tells Mitchell that she killed herself, he is initially upset, but then claims that her being "weak" led to her suicide, not his actions.