Eisenegger began as a watchmaker at ETA in Grenchen, where he lead the development of the Co-Axial escapement for Omega. He had previously known George Daniels and suggested to ETA management that his escapement ideas could be productized in 1993, and lead the development through 1999.
He then went to work with IWC under the leadership of Günter Blümlein, where he met Georges Kern. At IWC, Eisenegger is credited for improving the reliability of Cal. 5000 in and leading the development of the movement for the IWC Big Pilot's Watch.