In the configuration‐based approached in 3d or 4f impurities in metals, the bare impurity states are taken as conventional ionic‐type several‐electron states, corresponding to well‐defined configurations 3dn or 4fn with intraconfigurational splitting into L−S terms, crystal‐field levels, etc. The condition for the impurity to remain ’’magnetic’’ as the interaction with the conduction electrons is switched on is that the stabilization energy of the bare‐impurity ground state, relative to levels belonging to higher configurations, be large compared to the mixing width. Under this condition, the ionic‐type intraconfigurational structure of the impurity also continues to be defined. Although a different historical line of development hindered its recognition, there is good evidence for such ionic‐type structure in 3d as well as 4f impurities. Our conclusion is that a configuration‐based description is the most physical one for a magnetic impurity. This conclusion has interesting implications for the theory of magnetism in concentrated metallic systems.