From 1 December 1886 he worked as permanent teacher at the Städtische Gymnasium zum Heiligen Kreuz (Kreuzschule) by the will of the council of city Dresden.

The Verein zur Förderung des mathematischen und naturwissenschaftlichen Unterrichts (development association for mathematics and natural science classes) played an essential role for the reforms movement, esp.

As, in the run of these reforms, differential and integral calculus found entrance to the curriculum of secondary schools for the first time (since 1907 in Saxon), a representation of this subject area was needed which was fitting for these students.

His booklets on differential and integral calculus were published since the middle of the 1930s in the Göschen compilation – in a highly extended form and supplemented by separate exercise books.

For several years from 1911 on, Alexander Witting additionally published Verhandlungen der Gesellschaft Deutscher Naturforscher und Ärzte (Proceedings of the Society of German Natural Scientists and Doctors).

Beside others in World War I he was supervisor of a gas defence course for officers in Dessau and was deployed at a mortar school, reaching the rank of major.

On his 75th and 80th birthdays he received several official congratulation letters, for instance from the publishing companies Teubner and de Gruyter, but also from the Deutsche Mathematiker-Vereinigung (DMV).

In November 1945 Witting's Aufruf zur Rettung der höheren Schule (call for rescue of secondary school) was published posthumously in Physikalischen Blättern.