Day grew up in Ocean County, New Jersey, and graduated from the University of Mary Washington in 1997. She was an intern for the fashion magazine InStyle before being hired as an editorial assistant for the Sports Illustrated Swimsuit Issue in 1998.[1][2] In 2013, she oversaw the launch of the website Swim Daily, which promotes the swimsuit issue and its models year round. She became the swimsuit issue's top editor the following year.[2][3]
During her tenure, the swimsuit issue has introduced a greater range of body types and placed a focus on body positivity and women's empowerment.[4][5][6] Robyn Lawley was the issue's first plus-size model in 2015.[5][7] In the 2017 issue, Nina Agdal wore a tank top reading "A Woman Does Not Have to Be Modest to be Respected", while in 2018, models chose their own words and messages to display in body paint in one spread.[4][8] Leyna Bloom was the magazine's first openly transgender cover model in 2021.[6]