1831 he was sent by the government to examine the cholera in Bohemia, Moravia and Silesia. In 1834 he was appointed to the post of the personal physician to the then crown prince and later king Maximilian II of Bavaria. In addition in 1838 he became professor at the University of Munich and from 1842 to 1851 Director of the Municipal Clinic of Munich (Klinikum links der Isar). With the end of the winter semester 1885/1886 he retired as lecturer because of his advancing heart disease.
Gietls work focussed on Cholera and Typhoid fever esp. clinical observations and their treatment. In addition he published on Erysipelas and statistical observations at the Municipal Clinic.