One of the notorious difficulties with field theory is its prediction of nonsensical infinite values for physical properties such as energy. Renormalization is a procedure by which divergent parts of a calculation, leading to the nonsensical infinite results, are absorbed by redefinition into a few measurable quantities, so yielding finite answers. This work shows that renormalization counterterms added to field-theoretic Hamiltonians and Lagrangians are a consequence of direct-particle-action corrections to field theory. Some widespread misunderstandings are also corrected. Most physicists ignore the physical and mathematical differences between direct-particle-actions on Coulomb and Newton theories and contact-actions in field theories and General Relativity. If you check standard textbooks, as the one by Steven Weinberg [1] , you can see that he claims on the section 8.3 that the field-theoretic quantity \[ V_\mathrm{field} = \frac{1}{2} \int \mathrm{d}^3 \boldsymbol{x} \int \mat