Louise Acker is an American actress. She is best known for starring as
Winifred Burkle and Illyria on the supernatural drama series Angel
(2001–2004), as Kelly Peyton on the action drama series Alias (2005–2006),
and as Root on the science-fiction drama series Person of Interest
(2012–2016). As of 2017, she stars as Caitlin Strucker on the superhero
drama series The Gifted, based on Marvel Comics' X-Men.
Acker made her major television debut when she starred as Winifred "Fred"
Burkle in Angel (seasons 2–5), and also as the character of Illyria for
part of the show's fifth and final season. She won the 2003 Saturn Award
for Best Supporting Actress on Television for her portrayal.
She joined the cast of Alias in 2005 for its final season, playing
villainess Kelly Peyton. Acker graduated from guest star to fully credited
cast member as the show entered the final episodes in April and May 2006.
Also in 2005, Acker provided voice acting for the character of Huntress on
the animated series Justice League Unlimited. She went on to make a guest
appearance on How I Met Your Mother, in which she was reunited with Angel
co-star, Alexis Denisof (the real-life husband of HIMYM star Alyson
Hannigan), who had a recurring role on the show.
Acker portrayed Dr. Claire Saunders/Whiskey, a recurring character, on
Joss Whedon's Dollhouse. She guest-starred in 10 of the 13 episodes of the
first season and three episodes of the second.