A timeline of production, casting, and other non-narrative events in Legion history.
2015[]
- Wednesday, October 14 - Pre-production announced [Vulture]
2016[]
- Tuesday, January 5 - Rachel Keller joins cast [Deadline]
- Thursday, February 4 - Aubrey Plaza, Jean Smart, and Dan Stevens join cast [Entertainment Weekly]
- Thursday, February 18 - Jeremie Harris joins cast [The Hollywood Reporter]
- Monday, February 22 - Amber Midthunder joins cast [Deadline]
- ? - Hamish Linklater joins cast
- March - Production begins
- Tuesday, March 1 - Katie Aselton joins cast [Entertainment Weekly]
- Thursday, October 6-Sunday, October 9 - New York Comic Con 2016 - First half of pilot shown
- Monday, October 10 - Jemaine Clement joins cast [ScreenRant]
- ? - Bill Irwin joins cast
2017[]
- Sunday, February 5 - Legion has 8 ad spots during Super Bowl LI
- Wednesday, February 8 - Chapter 1 airs
- Wednesday, February 15 - Chapter 2 airs
- Wednesday, February 22 - Chapter 3 airs
- Wednesday, March 1 - Chapter 4 airs
- Wednesday, March 8 - Chapter 5 airs
- Wednesday, March 15 - Chapter 6 airs
- Wednesday, March 22 - Chapter 7 airs
- Wednesday, March 29 - Chapter 8 airs
- Thursday, July 20 - Saïd Taghmaoui joins cast [Variety]
- Thursday, July 20–Sunday, July 23 - San Diego Comic Con 2017 - Season 1 panel; Sessions: The Legion Mixed Reality Experience art display
- Tuesday, November 28 - Saïd Taghmaoui exits cast [Variety]
2018[]
- Friday, January 5 - Navid Negahban joins cast [TVLine]
- Tuesday, April 3 - Chapter 9 airs
- Tuesday, April 10 - Chapter 10 airs
- Tuesday, April 17 - Chapter 11 airs
- Tuesday, April 24 - Chapter 12 airs
- Tuesday, May 1 - Chapter 13 airs
- Tuesday, May 8 - Chapter 14 airs
- Tuesday, May 15 - Chapter 15 airs
- Tuesday, May 22 - Chapter 16 airs
- Tuesday, May 29 - Chapter 17 airs
- Tuesday, June 5 - Chapter 18 airs
- Tuesday, June 12 - Chapter 19 airs
- Thursday, July 19–Sunday, July 22 - San Diego Comic Con 2018 - Season 2 panel; Goya Studios Legion Chamber art display
2019[]
- Wednesday, January 9 - Lauren Tsai joins cast [Variety]
- Monday, February 4 - Stephanie Corneliussen and Harry Lloyd join cast [Marvel]
- Tuesday, February 5 - Noah Hawley announces that season 3 will be the last season. [Associated Press]
- Friday, March 29-Sunday, March 31 - WonderCon Anaheim 2019 - Season 3 panel
- Monday, June 24 - Chapter 20 airs
- Monday, July 1 - Chapter 21 airs
- Monday, July 8 - Chapter 22 airs
- Monday, July 15 - Chapter 23 airs
- Monday, July 22 - Chapter 24 airs
- Monday, July 29 - Chapter 25 airs
- Monday, August 5 - Chapter 26 airs
- Monday, August 12 - Chapter 27 airs