Seidel's US television debut was as a Guest Star on
NBC Universal's police drama
Law & Order: Special Victims Unit's
season 12 premiere episode in 2010. She starred as
FBI Agent Sarah DeSoto in the
noir-feature film,
The Hollow in 2015, and as Sybille Ranisch in
Schmidts Katze in 2014. Seidel starred as Sigrid Mueller, the Norwegian wife to rogue Treasury Agent Nelson Van Alden (
Michael Shannon) in the
HBO TV drama series
Boardwalk Empire from
season 2 to
season 5 (2012 – 2015). As of 2015, Seidel is a member of the Scandinavian American Theater Company, In 2017, Seidel played Martha, a mysterious, free-spirited German stranger, in the Netflix mini-series
Godless, starring alongside
Michelle Dockery and
Jeff Daniels. In 2019, Seidel played the role of Hannah, mistress of
Bob Fosse (
Sam Rockwell) in FX television series
Fosse/Verdon. ==Personal life==