From 1921 to 1927 he worked with Ludwig Prandtl at the "Aerodynamische Versuchsanstalt" in Göttingen, witnessing a legendary period in the development of modern fluid dynamics.

After completing his PhD, Ackeret worked at Escher Wyss AG in Zurich as chief engineer of hydraulics, where he applied, with great success, modern aerodynamics to the design of turbines.

He led the initial work on calculating the lift and drag on a supersonic airfoil[2] and he proposed the designation of the "Mach number" for multiples of the speed of sound.

Ackeret was awarded the Ludwig-Prandtl-Ring from the Deutsche Gesellschaft für Luft- und Raumfahrt (German Society for Aeronautics and Astronautics) for "outstanding contribution in the field of aerospace engineering" in 1965.

In 1976, he was elected foreign associate member of the American National Academy of Engineering for his "contributions to the understanding of high-speed and supersonic fluid mechanics, leading to significant improvements to the science of flight".