Lucy has fair skin and light brown short hair with longer sides framing her rounded face and bangs covering her forehead. Her eyes are an oval shape and colored a deep crimson.
She usually wears a green blouse that resembles a military jacket with golden buttons. It has belts and buckles as accessories on the hem of the sleeves and on her hips, on which she puts her Scotland Yard badge. She also wears knee-length white trousers and, beneath them, grey stockings which cover her calves. Her shoes are rounded white and brown pumps with white shoelaces, and her hat a salmon-colored newsboy beret cap, which sometimes moves slightly when she jumps in surprise.
Lucy acts highly optimistic and confident, never shying away from her mistakes and troubles, always willing to aim for better and trying her best to solve any problem or crime. As Alfendi himself commented, Lucy possesses proven good intuition, and displays great curiosity and willingness to learn new things. She is also very forthright in her expression, being very honest and direct about her thoughts and feelings, to the point of coming across blunt or incorrigible in certain situations.
Additionally, she sometimes displays a level of stubbornness and recklessness, often jumping to conclusions and forging ahead without considering the risks and dangers. Alfendi once described her as a "daredevil" - a statement worded without compliment.
Lucy exhibits a strong sense of empathy, even when threatened with grievous danger or spoken to rudely by those with which she empathizes. As Alfendi would later mockingly proclaim, Lucy never fails to 'see the good side of people'.
Some time prior to her assignment to the "Mystery Room", Lucy took her detective's exams, in which she did poorly, but was able to pass. On her first day on the job, Lucy met with Scotland Yard's Deputy Commissioner Chan, who scolded her for not paying attention to him. She apologised for her mind being elsewhere but suggested that the good weather was a good omen for her new career. Unimpressed, Chan told her that she had been assigned to a 'back office' that could be closed down at any time, but she replied that the said location was where all the unsolved crimes were sent - 'where the real stinkers get cracked'. Commissioner Barton appeared, agreeing with her and adding that she had been assigned to a very talented inspector whose deductive powers were known to be among the best in the Yard. Thanking the officers, she rushed off, leaving the two men behind.
Upon arriving at the office, Lucy found no one inside, and resolved to practice her pinpointing of suspects. In the middle of her performance, however, she found herself face to face with Alfendi Layton. As Lucy apologized, she introduced herself as his new assistant, telling him that she wanted to learn a lot and that she hoped he'd show her the way. Thinking of him as her mentor, Lucy dubbed him "Prof". However, Alfendi questioned the name, telling her that his father had been a real university professor. Unperturbed, Lucy continued to refer to him by the name, prompting him to tell her that he hadn't yet decided whether she had a permanent position as his assistant or not. To that end, he gave her an ongoing case with which he could test her abilities and she prove her worth to him.
- As revealed in a conversation between herself and Dolly Hollerday, Lucy is 22 years old during the events of Mystery Room.
- Her speech pattern consistently replaces the word "was" with its plural "were". An example of this is "I were miles away" as opposed to "I was miles away". It is inferred from Lucy's diction and vocabulary in the game that she speaks with a Lancashire accent.
- While Lucy's hair matches a light brown, in the case 'Who Killed Pig?' if you choose Cat as the culprit, Diane Makepeace will call Lucy a 'dozy ginger', suggesting Lucy's hair is supposed to be red, or at least reddish.
- In Layton's Mystery Journey, Katrielle Layton is twice depicted writing a letter to Lucy, indicating that the two know each other and are friends.