The landmark 300th episode of Supernatural brought with it a pleasant surprise in the form of the return of Sam and Dean’s father John, also bringing back Jeffrey Dean Morgan to portray him. However, despite Morgan originating the character, the producers initially wanted Bruce Campbell to play the older Winchester patriarch.
Of course, this never came to pass and the emotional episode saw the brothers temporarily reunited with their dad played by Morgan, only for the magic of the circumstances to pull John from the past and inadvertently alter history in the process.
The story came to light when Jensen Ackles was interviewed on Michael Rosenbaum’s podcast Inside of You, with the actor saying:
“They actually went out to Bruce Campbell to play present-day Dad. That was the only person that they wanted. Ultimately, they couldn’t make it happen, whether it was [because of his] schedule or whatever. So they kind of threw their hands up in the air, and [were] like, ‘Well, maybe we can just age Jeff up and have him come back and play an older version of himself’.”
As popular an actor as Campbell is, he was most likely selected as a reference to his having been series creator Eric Kripke’s first choice to play John, but was unavailable for the role as around that time he would have been busy filming trashy sci-fi action movie Alien Apocalypse or directing his own feature debut in the form of comedy horror The Man With the Screaming Brain.
Morgan has been a part of Supernatural from its very beginning, of course, playing John in the 1983-set prologue of the pilot episode, and thought the role would be recast when the character returned in the then-present of 2005, as by that point, John would be over 60. This led to an in-joke among fans of the series regarding the actors’ comparative ages, with Morgan being only 12 years older than Ackles, and the latter now being several years older than Morgan was when the series began.
Whatever the reason for Campbell passing on the role a second time (perhaps being uninterested in playing a distinctly older version of a man only eight years his junior), it was probably for the best, as the return of John would not have had as much of an emotional impact for the viewers of Supernatural had it been any actor other than Morgan playing him, even one as iconic and popular as Campbell will always be.