Legion: Cast Legion Science-Fiction, Drama, Action 2/8/17 – 8/12/19 United States http://www.fxnetworks.com/shows/legion GeneralEpisodesCastCharactersGallery Cast See full cast → Jean Smart as Melanie Bird Amber Midthunder as Kerry Loudermilk Aubrey Plaza as Lenny Busker Dan Stevens as David Haller Rachel Keller as Sydney "Syd" Barrett Bill Irwin as Cary Loudermilk Jeremie Harris as Ptonomy Wallace / Mainframe Hamish Linklater as Clark DeBussy Katie Aselton as Amy Haller Navid Negahban as Amahl Farouk / The Shadow King Jemaine Clement as Oliver Bird Lauren Tsai as Jia-yi / Switch Harry Lloyd as Charles Xavier
