Kießig studied Protestant church music and jazz piano at the Hochschule für Musik und Darstellende Kunst Frankfurt am Main, on a scholarship of the Hanns-Seidel-Stiftung.
In 2013, Kießig became referent for pop music at the Evangelische Landeskirche in Hessen und Nassau.
Beginning in 2018, he has also worked as pianist for the dance faculty at the Hochschule für Musik und Darstellende Kunst Frankfurt.
[1] He was commissioned to compose parts of the oratorio Eins for Ökumenischer Kirchentag 2021 in Frankfurt.
[2] It was published by the Dehm-Verlag[2] and first performed in a livestream concert on 4 May 2021,[3] with Kießig as the pianist.