With the entry into the Westphalian era and the formation of nation-states, conscription became a source of military power for European countries. With the end of the Cold War and the emergence of new threats, European countries moved towards the transition from conscription to professional volunteer armies. The concept of a professional army is used to describe an army that is mainly composed of professional military personnel as opposed to conscripts. Globally, the professionalization of armies has been accompanied by improved training, advanced technical equipment, standardization of recruitment and promotion methods based on merit, professional ethics, and increased specialization. This article aims to examine the requirements and operational mechanisms of the European Union in shaping modern armies. The analytical framework of the article is based on the three main components of Huntington's professionalism (specialization, responsibility, and corporateness), which have been redefined with new dimensions in the context of the European Union. The research findings show that, in addition to improving specialized training and strengthening civilian oversight, EU mechanisms place special emphasis on developing professional ethics as an independent dimension, including human dignity, transparency, and ensuring the socio-civil rights of military forces, such as competitive benefits, the right to association, and whistleblower protection. The research method of the article is descriptive-analytical, and the data were collected from reputable global scientific sources.