The cell’s interior is a complex milieu where proteins exist in an environment crowded with other macromolecules. The influence of macromolecular crowding is prevalent in every cellular function—from metabolism to signal transduction to protein folding. It is even hypothesized that macromolecular crowding dictates the organization of the intracellular environment and the evolution of a single-cell species. Even though proteins are prevalent in every biochemical process, we lack fundamental knowledge about how crowding affects proteins. When studying proteins in a crowded environment, one can either develop a system that mimics the cellular interior or develop a technique that observes proteins inside cells. Herein, I report a residue-level interrogation on the stability of chymotrypsin inhibitor 2 under macromolecular crowded conditions. This is the first study that offers comprehensive information about the effects of crowding on the stability of the native state of a globular protein. I also present observations about the behavior of globular, partially-folded, and natively-disordered proteins inside living E. coli and the consequences for in-cell NMR. Lastly, I discuss our progress in transitioning from in-cell NMR for living E. coli to the yeast, Pichia pastoris.