Born in Strasbourg, Valentin, the son of a postal clerk, studied musicology at the Ludwig-Maximilians-Universität München from 1925 and was awarded a doctorate in 1928 with his dissertation Die Entwicklung der Tokkata im 17. und 18.
In 1935, he proved to be a loyal partisan of the NS-regime, when he wrote in Musikgeschichte als Bildungsfaktor an article titled "Das Bildungsideal des neuen Staates ist wie sein politisches Ziel die Totalität".
[1][3] After the Anschluss, he was appointed teacher at the Mozarteum in Salzburg in 1939, where he became lecturer for musicology and director of the Central Institute for Mozart Research.
From 1946 to 1947, he was a teacher at the home school Burg Sternberg [de]/Lippe, and from 1949 to 1953 a lecturer at the Hochschule für Musik Detmold.
Ein Lesebuch vom Wesen und Werden deutscher Musi (Bosse, Regensburg 1940) was placed on the List of literature to be discarded [de].