After graduation, Kristín Þóra was employed by the Akureyri Theatre Company, where she played in Óvitar, Ökutímum, and Fló on Skinn.
In spring 2008, she was employed by the Reykjavík City Theatre and in the National Theatre of Iceland, where she has appeared in several plays: The West One, The Ruins, The People in the Cellar, The Hurricane, The Styrian Pet, The Darling Child, Fanny and Alexander, Tengdó, Little Hamlet, Wishbone, Socrates, Flood, along with the advertisement of the year, The Strip, and God Bless Iceland.
From recent film projects, she has appeared as the lead role in two films, Sundance winner and international hit film And Breathe Normally (Icelandic: Andið Eðlilega, 2018) directed by Ísold Uggadóttir playing the role of Lára, and as the character Magnea in Let Me Fall (Icelandic: Lof mér að falla, 2018) directed by Baldvin Z, which premiered at TIFF in 2018.
Kristín Þóra was selected in the group "Shooting Stars" 2019 by European Film Promotion.
Each year they select ten promising actors and actresses from among their members, who have received special attention in their country and internationally.