John Connally

Johnnie was riding in the limousine with President John F. Kennedy and his wife Jackie Kennedy in Dealey Plaza, Texas when the former was assassinated by Lee Harvey Oswald (PROSE: Untitled) or James Stevens. (PROSE: Who Killed Kennedy) When Kennedy was shot, Johnnie "[fell] down". (PROSE: Untitled)

He was seen sitting in the seat directly in front of Kennedy and waving to the crowds in a photograph taken just prior to the assassination. This photograph was retrieved by Clive Finch from the Washington public archive in 2004. (TV: Rose) Adam Mitchell also later obtained it. (COMIC: Mystery Date)

Behind the scenes
In Untitled, Connally is only referred to as "Johnnie" but the common sense interpretation was that it referred to him. Additionally, although it is unclear from the text, in the real world Johnnie did fall down but was not fatally injured.