Ruth Killius began playing the viola at the age of four. She studied with Ulrich Koch and Kim Kashkashian and honed her skills through classes and chamber music with Wolfgang Marschner. She was named a chair at Mainz, where she regularly teaches.
Through a commission from the Salzburg Festival, Heinz Holliger worte Janus, a double concerto for violin, viola and small orchestra for Ruth and her husband, Thomas Zehetmair. John Casken’s double concerto That Subtle Knot is also dedicated to the couple.

In 1994, Ruth Killius and her husband founded the Zehetmair Quartet, which has become one of the world’s finest string quartets. Their recording of Schumann’s First and Third Quartets won them a Gramophone Award, Edison and Klara prizes and the Diapason d’Or.
Their recording of the Hindemith’s Fourth and Bartok’s Fifth String Quartets was also awarded the Diapason d’Or of the year. The quartet then went on to win the Hindemith Prize of the City of Hanau. The quartet’s latest album is dedicated to the music of Beethoven, Bruckner, Hartmann and Holliger.

Ruth Killius, meanwhile, has recorded a CD containing the works of Elliott Carter and Isang Yun with Heinz Holliger on ECM.

Her recording of Mozart’s Sinfonia Concertante with the Orchestra of the Eighteenth Century, conducted by Frans Brüggen and released by the label Glossa, is considered a reference recording.

In duet with Thomas Zehetmair, Ruth Killius has performed at numerous musical centres. ECM released their album Manto and Madrigals in March 2011 with works by Scelsi, Bartók, Holliger and Martinů, among others.