John Walker was the field leader of the Invaders and a US Marine. He appeared in The Invaders and was portrayed by Jack Hutson.
John Walker was a United States Marine who fought under the command of Major Robert Frank in Belleau Wood in June 1918. Through the trauma of the battle, John developed Shell Shock and Railway Spine- the predecessors to PTSD.
- In prior version of the film, both John Barrowman and Scott Eastwood were planned to play Walker. Jack Hutson was the final choice and Eastwood and Barrowman remain in the movie as different characters: Robert Frank and Silas Burr.
- In the comics, John Walker is the Captain America after Steve Rogers during the Cold War. In the MCU, the role is filled by Isaiah Bradley.
- In the final drafts for the final version of the film, Jack Hutson was planned to take the role of Heinrich Zemo instead of Leonardo DiCaprio. He was given the role of John Walker instead.