Was Gary Mitchell Originally the First Officer?

[Gary Mitchell]

But the things you could do, like... maybe a god could do.

Yeah but last time he tried that Kirk and Spock tried to dump him on a shitty planet, and I've seen the new movie version its ever worse!

Yeah, but I moved Delta Vega from the edge of the galaxy to within spittin' distance of Vulcan. True, it's a little snowier than I would like, but Kaferian apples thrive in the cold.

 

[stoneagepunk]

Noncanonly Kirk wanted Mitchell to serve as his Executive Officer when he was assigned to the Enterprise; however, Starfleet didn't want this because they felt Kirk and Mitchell were too much alike. Because of this Command assigned Spock as first officer despite Kirk's objections.

Yes I read that too in one of the prequel stories, "The first mission".