[1][2] Yoon was born in Champaign, Illinois to parents of Korean descent in 1962 and subsequently raised in Toronto, where she currently resides and works.

[3] Yoon started her career in theatre as an actress in the early 1980s, but soon quit in frustration after she struggled to find work and went on to complete her degree at the University of Toronto (BA Innis 1989[4]).

[5] A decade later, in 1995, she returned to acting and started her own group called Loud Mouth Asian Babes, through which she has written and produced plays that focus on the Korean diaspora, mostly in Canada.

[5] Yoon's acting career began to flourish in the early 2000s, with small roles in several television series, including La Femme Nikita (1996–2001), Witchblade (TNT, 2000–2002) and Street Time (Showtime, 2001–2003).

For her role in the television series, she has received considerable attention and has publicly discussed the importance of diversity in mainstream media, specifically for Asian Canadians and immigrants.