Non‐activated esters are prominently featured functional groups in polymer science, as ester functional monomers display great structural diversity and excellent compatibility with a wide range of polymerization mechanisms. Yet, their direct use as a reactive handle in post‐polymerization modification has been typically avoided due to their low reactivity, which impairs the quantitative conversion typically desired in post‐polymerization modification reactions. While activated ester approaches are a well‐established alternative, the modification of non‐activated esters remains a synthetic and economically valuable opportunity. In this review, we discuss past and recent efforts in the utilization of non‐activated ester groups as a reactive handle to facilitate transesterification and aminolysis/amidation reactions, and the potential of the developed methodologies in the context of macromolecular engineering.