- Wheeler Professor of Performance at Oberlin Conservatory, 42 years.
- Founder/Director of the Vocal Arts Center (OBSVAC) at Oberlin Conservatory
- Collegium Medicorum Theatri member
- American Academy of Teachers of Singing
- Otolaryngology Adjunct Staff, Cleveland Clinic Foundation
Miller taught for 28 years at the Mozarteum International Summer Academy in Salzburg, Austria. He presented lectures and classes at the Paris Conservatoire Superieure, at the Marseilles National Opera School, and at Centre Polyphonique.
In November 2005, he retired from the Oberlin Conservatory, where he had taught for more than forty years. After retirement, he continued to teach some masterclasses. Internationally renowned for these masterclasses, he taught in Austria, Australia, Canada, England, France, Germany, New Zealand, Norway, Portugal, Sweden, Switzerland, and 38 US states.