Holt's acting debut was in 1991, appearing in the film Black Robe. She has appeared in Rapa Nui, the telemovie and subsequent TV show Once a Thief, Pocahontas: The Legend, 1999 and Resident Evil: Apocalypse.
In 2006, she appeared in a recurring role on the television series 24 as Evelyn Martin, the aide to First Lady Martha Logan. In 2007 she appeared in the recurring role of Catherine Rothberg in Showtime's series The L Word.
In 2012, she appeared in Underworld: Awakening as Lida, an Antigen employee who took care of the protagonist's daughter, a prisoner named Subject Two.
In 2013 she appeared in House of Cards season one as Gillian Cole, the leader of a grass-roots organization called World Well that provides clean water to developing countries.
In 2015, she appeared in the film Terminator Genisys, and the TV series Fear the Walking Dead.
In 2016, she appeared in MacGyver as Patricia Thornton, an ex-field agent turned Director of operations for DXS.
