Question as in the title:
Who was Hermann Künneth? Where can I find some biographical information beyond what is available on Wikipedia?
The well-known Künneth formula, for example in the form of exactness of the sequence
$$
0 \to \bigoplus_{p+q = n} H_p(C) \otimes H_q(D) \to H_n(C \otimes D) \to \bigoplus_{p+q=n-1}\operatorname{Tor}_1(H_p(C),H_q(D)) \to 0,
$$
for complexes $C$ and $D$ of flat modules over a PID appears prominently in essentially every book on homological algebra and algebraic topology. Of course, Künneth formulated his insight in terms of Betti numbers, not in terms of homology groups.
Nevertheless, biographical information on its originator seems quite hard to find.
Wikipedia links to Haupt's 5 page obituary in German which mainly focuses on Künneth's mathematics with only a few lines dedicated to his life.
Any further pointers would be appreciated.
Best Answer
For the sake of the readers who are not fluent in German, I provide a translation of the German Wikipedia page (link to the revision at the time of posting this answer):
Hermann Künneth (1892-1975) was the son of the high school ("Gymnasium", the highest form of high school) teacher Christian Künneth. Beginning with 1910, he studied mathematics at the Universität Erlangen and the Ludwig-Maximilians-Universität München with a "break" from 1914-1919 where he served in the German army; he was injured twice and was prisoner of war with the British. Künneth was member of the AMV Fridericiana Erlangen, a musically oriented fraternity. His professors in Erlangen were Ernst Sigismund Fischer, Paul Gordan, Max Noether, Richard Baldus and Erhard Schmidt.
1912 he took his first Staatsexamen to become a teacher and 1920 he took his second. In 1920 he became teacher in Bavaria, in particular at high schools ("Gymnasien") in Kronach and Erlangen. He remained in contact with the University in Erlangen, where he got in PhD under the direction of Tietze in 1922 (and was assistant (professor) beginning with 1921). The title of his thesis was "Über die Bettischen Zahlen einer Produktmannigfaltigkeit" - "About the Betti numbers of a product manifold" (where he proved the Künneth formula).
1923 he became assistant (professor) in Berlin; interestingly, he became 1923 also teacher ("Studienrat") in Kronach. As already indicated, the switched to the high school Fridericianum in Erlangen in 1925, where he became Oberstudienrat in 1950 [this would not be a very high position at a high school these days, but I am not sure how it was then]. In 1942 he habilitated in Erlangen and was Privatdozent (a kind of freelancing professor) after that. After he retired in 1957 from his teaching job, he became associate professor in Erlangen. Otto Haupt said about this: "[he] developed an amazing and surprising scientific activity." (at the age of 65)
1964 he got the Bundesverdienstkreuz am Band (the second lowest order of the "Order of Merit of the Federal Republic of Germany"). (See this newspaper article - it says: "His chivalric personality, of clear judgement, emanates human kindness and witty humour.")