At only 26 years old, Jaeger was called to the professorial chair in Greek at the University of Basel in Switzerland once held by Friedrich Nietzsche.
One year later, he moved to a similar position at Kiel, and in 1921 he returned to Berlin, succeeding to Ulrich von Wilamowitz-Moellendorff.
Jaeger's messages were fully understood in German university circles, with Nazi academics sharply attacking him.
He then moved to Harvard University to continue his edition of the Church father Gregory of Nyssa on which he had started before World War I. Jaeger would remain in Cambridge, Massachusetts, until his death.
Jaeger's position concerning the history of the interpretation of Plato and Aristotle has been summarized by Harold Cherniss of Johns Hopkins University.