Hailey had a run-in with Trudy Platt when she accidentally spilled coffee all over her. Trudy was very unimpressed, but this changed when Hailey saw her name. She asked if she'd worked in Homicide, and Trudy said she did.
Hailey told Trudy that when she was in her early teens, Trudy helped her and her father after a robbery. She said that Trudy was the reason she became an officer.
Hailey was shown to be slightly impulsive when making decisions, which was shown because she didn't stop to plan when she suggested many of the plans. This could be because she worked in a different unit.
Hailey had a clash with Voight after his unit was called to a bank robbery, but Hailey's unit, Theft and Homicide, had been working on the case for longer. Voight said it was murder but Hailey claimed that she had been tracking the group of robbers for longer.
After some hassle, the two were told to work together. Hailey was fast in investigating the robberies and Voight was impressed. He told her at the end of Fagin that a spot in Intelligence had opened up (after Kim left) and she was free to take it. She didn't reply.
In Army of One it was revealed that she took the job. She was paired with Erin after Hank made the decision to split up Erin and Jay.. Lindsay then raged out over a case where a small child was kidnapped. As time was running out, she went into the interrogation room with her gun, breaking protocol. Hailey tried to stop her and went in after her to get her out but was unsuccessful. Lindsay told her to leave, which she didn't. Later on, Lindsay was called in front of the board because she threatened the suspect with a gun, and was suspended.
In Fork in the Road, Platt told her to carefully think over what she was going to say to the board. She said it was clear to both her and Lindsay what happened and they wouldn't need to lie. However, the board was adamant on suspending Erin and disregarded Hailey's statement. Platt told her to watch out because she had just transferred to Intelligence and was already in front of the board within a week.
Ruzek was called in for a review after he punched a suspect in Snitch. He went to see Hailey, who had been with him and stopped him from continuing. He said it was straight-forwards and expected her to say he didn't do it. She said that there are CCTV cameras and phones everywhere to record these types of things, and that she needed to consider this carefully. This angered him and she said that she had told him to not go off like that.
Later on, Hailey praised Jordan Atwater for speaking the truth when it endangered his life. Adam saw this is as a statement aimed at him, and called her out in front of everyone. Antonio told him to let it go, but he went after Hailey and told her that if she has such a problem covering his back, she should tell him. She told him that the only eye-witness who spoke out against Adam had taken her statement back after she talked to them. Adam questioned her and asked how she "just" took it back, to which Hailey replied that she never said it was that easy. He thanked her, but she said she didn't do it for him, angered.
She is very hard-working and while she can come off as rude, she is also very considerate of others. This was seen multiple times when she told Lindsay she could do anything, including transferring out, to make her feel better after she noticed how stressed Erin was.
She is also protective of her teammates. She convinced a witness to retract a statement that would have gotten Adam in trouble for punching a suspect, and also released another suspect in exchange for not not telling anyone that she and Jay had dated while he was undercover, as it would have ruined his career.
Hailey's first encounter with Platt at Intelligence ended up with her dropping coffee on Platt. This immediately angered her, especially when Hailey didn't apologise. However, when Hailey saw her name, she recognised her. She told her that Platt had been the officer on scene to a robbery and murder, which was of her father. She said Platt motivated her to become a police officer. After that, Platt tried to look out for Hailey in her first week.