Robin Weigert (born July 7, 1969) is an American actress. She is best known for portraying Calamity Jane on the television series Deadwood (2004–2006), for which she received a nomination for the Primetime Emmy Award for Outstanding Supporting Actress in a Drama Series in 2004, Ally Lowen in Sons of Anarchy (2010–2013), Dr. Amanda Reisman in Big Little Lies (2017–2019), and Abby in Concussion (2013).