From 1919 until 1934, Jetzinger served as social democratic assemblyman in the federal state Diet (electoral district Innviertel).
After he had worked as deputy for two years, Jetzinger became District Administrator in 1932 and therefore member of the Upper Austrian federal state government in Linz.
He attracted attention by attacking an earlier published book The Young Hitler I Knew by August Kubizek, whom Jetzinger accused of spreading falsehoods[citation needed].
In 2006, Ian Kershaw opined that Jetzinger's scholarship is, in fact, not invariably superior to Kubizek's vivid pen-picture of the young Hitler, and contains some weaknesses of its own, both factual and interpretative.
[1] Still, Jetzinger's work remains relevant in the 21st century: In 2007, BBC Radio 4 broadcast a radio play titled Dr Freud Will See You Now, Mr[s] Hitler, a largely counter-factual work written by a pair of established Jewish screenwriters who credit Hitler's Youth for the factual basis which launched their enterprise a decade earlier.