Jan Dodonna is a human male military officer from Commenor who served in the navy of the Galactic Republic during the Clone Wars, then in the navy of the Galactic Empire, and finally as a general in the rebellion against it. He was played by Alex McCrindle in Star Wars: Episode IV A New Hope (1977).
The job
Dodonna is part of Alliance High Command, leading its Sector Command, and he is the military leader of the Rebellion’s hidden fortress on Yavin 4. When the plans reach the base, it is his analysis that produces a plan of attack, and his briefing that sends thirty pilots into the trench.
The briefing
It is worth taking seriously as a piece of writing, because it is doing four jobs in under three minutes. It establishes the objective — a two-metre thermal exhaust port leading to the main reactor. It establishes the constraint: the shaft is ray-shielded, so only a proton torpedo will work. It establishes the odds, out loud, in front of the people who will have to beat them. And it establishes the theme, in the line that explains why any of this is possible at all: the Empire doesn’t consider a small, one-man fighter to be any threat, or they’d have a tighter defense.
That sentence is the entire political argument of the original film compressed into fourteen words. Every subsequent Star Wars briefing scene — Hoth, Endor, Scarif, Starkiller, Exegol — is a variation on it, and most of them are worse.
The officer he was before
The reference material gives him a career on the other side of the line first: Republic navy through the Clone Wars, then the Imperial navy the Republic became, then defection. Star Wars has always been quietly full of these people — Crix Madine, Biggs Darklighter, Hobbie Klivian — and Dodonna is the most senior of them. The Rebellion’s command staff is substantially made of men and women who once wore the uniform they are now shooting at.
The recommendation
He also does the small, human thing that starts the trilogy’s real plot. When Red Leader questions whether a farm boy is fit to fly an X-wing, Dodonna is the officer who accepts Biggs’ and Wedge’s word for it. Luke Skywalker flies at Yavin because a general took two junior pilots at their assessment.
In print
Both continuities have kept him busy either side of the film. He is a fixture of the Legends Yavin-era material and of the modern canon novels and comics that fill in the years between Rogue One and A New Hope, always in the same role: the professional who does the arithmetic before anyone gets in a cockpit.