"The Outlaw Josey Wales" was co-written by Sonia Chersus and Phil Kaufman, the latter of whom was the original director until Eastwood infamously fired him and took over the production. The debacle caused the Director's Guild of America to install the "Eastwood rule" thereafter: No one involved with a production can just get the director fired and take their job.
The result, whether because of Eastwood's considerable directing abilities or a brilliant script that wrestles mostly successfully with some dense Civil War politics, is still a pretty great movie. Eastwood smartly focuses on Wales not as some symbol of noble Confederates but as a man exhausted by war who wants to live in peace. By the end of the movie, the character isn't a lone warrior anymore but has built a life with friends and family — the opposite of the traditional Western hero seen in "The Searchers" and "Shane."
Eastwood said in 2011 that he always intended "Josey Wales" to be an anti-war Western: "As for Josey Wales, I saw the parallels to the modern day at that time. Everybody gets tired of it, but it never ends." (Wall Street Journal)
"The Outlaw Josey Wales" is currently streaming on Netflix if you want to see one of Eastwood's great 70s Westerns for yourself.
