Bernstein began WeWoreWhat in 2011 as a street-style photographer before it became a personal-style blog and a fast-growing Instagram account. She studied at the Fashion Institute of Technology, was named to the Forbes 30 Under 30 list in 2017, and launched a string of lines — Second Skin Overalls in 2016, swimwear with Onia, denim with Joe's Jeans, and a namesake size-inclusive line at Macy's in 2020, priced under $100 in sizes 00–24.
In 2020 she consolidated her labels under Shop WeWoreWhat, spanning swim, denim, overalls and active, and published a New York Times best-selling autobiography, This Is Not a Fashion Story. She also founded Moe Assist, a project-management and payments tool built for influencers' workflows.