The pair met at Parsons and turned their senior thesis into a first collection that Barneys New York bought in its entirety. In 2008 they introduced the PS1, a satchel that became the brand's signature. The label later moved its shows from New York to Paris, and has been honored with five CFDA awards — including Womenswear Designer of the Year three times.
In January 2025 McCollough and Hernandez announced they would cease designing for the house — staying on the board as minority shareholders — to take the reins at Loewe. Rachel Scott, founder of Diotima, was named creative director in August 2025.