- "I'm a mechanical genius, which means I understand in my mind and my heart how parts work together. That's why I love machines. Bolt and a wrench, chain and a gear, they just made sense to me, they fit. For a long time, I didn't feel like I fit anywhere, until I met you. And I knew then, just like I know how to assemble engines, that you and me, Toby, we fit. You're my home."
- —Happy to Toby
Happy Quinn-Curtis is the daughter of Patrick Quinn and his late wife Grace, the wife of Toby Quinn-Curtis, and a member of Team Scorpion. She is a mechanical and engineering prodigy. Happy was portrayed by Jadyn Wong.
Her mother died giving birth to her and this led to her father dropping her off at a hospital when she was two years old, stating he could no longer care for her. While growing up in foster care, she kept looking for a red truck with a dented fender, as it belonged to her father and she hoped he would come for her. In 2010 she married Walter so he could keep his visa and eventually get citizenship. The needed to remain married for seven years, but she was able to divorce him in 2016 after only six years, so that she could marry Toby. They were officially granted a divorce in "Plight at the Museum".
Happy has a hostile exterior, due to her being raised in the foster system. This is somewhat of an irony considering her name is happy and generally she is not as her name suggests. The trauma in the foster system caused her mistrust of people. She possibly has PTSD from her trauma and her flashbacks and aggression and avoidance of the memories she has. She normally keeps her emotions in check but gets angry quickly and tries to deal with her pain by turning it into anger. She is extremely distrustful of others and being hurt by them. Despite this, she truly does love her friends. She has a very strong personality and is also very independent but her worst fear is that Toby will leave her like everyone else, as seen in Dirty Seeds, Done Dirt Cheap.
- She was six years old when Walter got arrested by the FBI.
- Walter found Happy when she was paying people to act as her stand-in at fabrication competitions as she hates being judged.
- She has a photographic memory in addition to her 184 IQ.
- Happy is fluent in Japanese and Portuguese.
- Happy is seen driving a beige 2004 Toyota Tacoma.
- Happy released a single in Portuguese before she joined the team, titled Amigo Amigável (friendly friend).
- She dated Jake Gyllenhaal, and she went to Morocco to visit him while they were still dating.
- In Sci Hard, we learn that Happy has kept her maiden name but is now known as Mrs. Quinn, rather than being Mrs. Curtis or Mrs. Quinn-Curtis.
- She drives a motorcycle, and is know for her rash and fast driving.
- She and Paige Dineen are the only female members of Team Scorpion.
- She is the shortest member of Team Scorpion.