プリンシパル
In 2014, Seo had the opportunity to dance several full-length roles in her second year as principal, when three of ABT's senior principal ballerinas announced their retirement, placing Seo in line for several leading roles. In the 2016 ABT season, nearly ten years from Seo's lead role debuted, she along with the also promoted Principal dancer Cory Stearns, reprised their roles as Romeo and Juliet as first cast at the Wolf Trap National Park for the Performing Arts. Seo has said, "when I dance with Cory, I feel like I’m going back to those years". Seo also reprised her role as Princess Aurora in Sleeping Beauty. Alastair Macaulay of "The New York Times" on Seo's performance, "she has most revealed the distinctiveness, elegance and authority of an important ballerina". She commonly partners with Roberto Bolle, including Bolle's final performance with ABT.