Born to an eleven-child family, Odermatt first worked as a baker and pastry chef, but gave up this work for health reasons. After entering the police service, he obtained the right to photographically document car accidents, even though it was common practice only to require sketches. Odermatt had been fascinated by photography since the age of ten, when he had won a camera in a contest. He carried with him his two-lens Rolleiflex camera and its magnesium flash in order to collect evidence for official reports and to document police activity, later indexing these in the collection entitled Im Dienst [On Duty].
He did not restrict himself to inventorying road incidents (mainly collected in the series Karambolage, from which Harald Szeemann presented thirty-two images at the Venice Biennale in 2001), but systematically directed his attention to the picturesque aspects of everyday reality. His family, his neighbours and the region’s landscapes inspired the series In Zivil [Off Duty], developed as a counterpart to Im Dienst.