The New York Times has described her style and dancing to "exude an unhurried purity that sums up all that is lovely about ballet" and by Vogue as "unspeakably lissome".

Her teachers identified her skills and talents early on and within a short period of time she was offered full scholarships to study abroad at prestigious ballet schools.

She was again quickly promoted into the corps de ballet in March 2006 and then to soloist in August 2010 before finally being named as principal dancer in July 2012 by Kevin McKenzie, the artistic director of ABT.

[2] Seo enrolled for one year before leaving to study ballet in a professional training program in the United States.

[2] Seo began her formal dance training at age twelve; a relatively late start for a ballet dancer.

[13] Seo won the 2003 Prix de Lausanne Award in Switzerland and was offered a scholarship by Reid Anderson to attend the John Cranko Schule.

[18] She gained significant attention in 2009 when she performed the female lead in MacMillan's Romeo and Juliet, La Sylphide, and On the Dnieper.

[8][17] Cory Stearns, at the time a newly promoted member of the corps de ballet, partnered her as the other titular character of Romeo.

[15] Seo has been noted for her "lyrical and open" style and "unique feminine strength" by several critics including The New York Times, Dance Magazine, and KoreAm.

[24][26] In an interview with Pointe magazine, Seo said that she "prefers the mental and physical challenge of full-length ballets over repertory works".

[24] 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.

[29] Alastair Macaulay of The New York Times on Seo's performance, "she has most revealed the distinctiveness, elegance and authority of an important ballerina".