He was influenced by Carl Orff, Hans Werner Henze, Herbert von Karajan, August Everding and Claudio Abbado.

In 1978, Schmidt-Gaden founded the "Florilegium Musicum", a chamber orchestra for early music with original instruments.

[2][3] Schmidt-Gadens recordings with the Tölzer Knabenchor include Bach's Christmas Oratorio with the Collegium Aureum, Kleine Geistliche Konzerte by Heinrich Schütz, and sacred choral music by Orlande de Lassus.

A reviewer of Gramophone noted about their 1971 recording of the Christmas Oratorio that it "bursts forth with spirited expectation as the Nativity is vigorously explored".

[4] He took farewell from the Tölzer Knabenchor with a concert of four motets by Bach at the Stadtpfarrkirche in Bad Tölz in January 2016, opening the year of celebrating the choir's 60th anniversary.