Here's what to know about McCullough, including her statements about health care and feminism that have drawn some heat.
1 - 'We regulate nuclear power plants.'
Her specialization is radiochemisty.
McCullough also has an outreach program called "Science Exploration for Kids," through which she tries to get youth in her area as interested in math and science as she is.
"Seeing children having so much fun in science really gets my heart going," she says.
2 - Worldly experience
Before competing in the Miss USA pageant, McCullough graduated from South Carolina State University.
3 - Her thoughts on health care
"As a government employee, I am granted health care and I see firsthand that to have health care, you need to have jobs," she added. "We need to continue to cultivate this environment that we're given the opportunity to have health care as well as jobs."
4 - She doesn't consider herself a feminist
McCullough said during the pageant that she prefers the term "equalism" to "feminism."
“I try not to consider myself, like, this diehard, ‘I don’t really care about men’” type of woman, she explained.
"Women -- we are just as equal as men when it comes to opportunity in the workplace," she added.
5 - She's a sports fan
In Washington, D.C., McCullough likes to take in a ball game from time to time.
She also posted a video of her kicking off her heels to play some basketball.