He was awarded his master's degree in 1746 by the philosophical faculty of Leipzig and went in the following to Marburg to work as assistant professor lecturing history, statistics, natural and international law.
With financial support from King George III he travelled to Switzerland and France in 1751 and to Holland and England in 1759.
The work by which he is best known is his Staatsverfassung der Europäischen Reiche im Grundrisse (Constitution of the Present Leading European States, 1752).
In this work, he gave a comprehensive view of the constitutions of the various countries, described the condition of their agriculture, manufactures and commerce, and frequently supplied statistics in relation to these subjects.
Achenwall gave currency to the term Staatswissenschaft (politics), which he proposed should mean all the knowledge necessary to statecraft or statesmanship.