One class of protein polymers, elastin-like polymers (ELPs), have been extensively studied owing to their tunable stimuli-responsive properties. ELPs are monodisperse, biocompatible, and amenable to chemical modification and processing, allowing for the creation of various architectures such as nano-and microparticles, films and hydrogels. As such, they hold great potential in advanced functional materials, especially in biological applications such as drug delivery and scaffolds for tissue engineering. However, to be useful in real or engineered physiological settings, ELPs must be reliably stable and soluble. Furthermore, they must exhibit predictable stimuli-responsive behavior in a complex and dynamic solution environment. For example, for an ELP-based biosensor to function in biologically relevant conditions, it should ideally respond to a single stimulus, such as binding to a target biomolecule, while remaining insensitive to variations in local pH, electric potential, ion concentration, and the presence of other co-solutes, at least for the duration and conditions of the experiment. In bulk solution, the stimuli-responsive behavior of ELPs is characterized by a reversible transition between soluble, extended nanoscale polypeptide chains and micron-scale coacervates formed when the hydrophobic regions of the ELP seek burial through intra-and intermolecular association. This phenomenon, which has been referred to as coacervation, liquid-liquid phase separation (LLPS), aqueous two-phase systems (ATPS), and lower-critical solution temperature (LCST) behavior, has been exploited to create various architectures and assemblies. When coacervate assembly is not possible or favorable, such as when ELPs are end-tethered polymers to a solid substrate or in single-molecule simulations, single-chain ELPs will still undergo continuous collapse resembling a coil-to-globule transition, accompanied by changes to internal degrees of freedom, hydration, and stiffness. On the one hand, the LCST behavior of ELPs has proven to be highly modular; fusion or conjugation with an ELP domain marries stimuli-responsiveness to a wide variety of other functional molecules. On the other hand, the LCST behavior of the ELP is known to shift based on its fusion partner. For example, when using the LCST behavior of an ELP fusion as a nonchromatographic purification strategy, different ELP tags may be needed based on the solubility behavior of the desired tagged protein. Currently there are valuable models for how ELP LCST behavior is tuned by the sequence length and composition of the ELP, including pH-sensitive ionizable residues, the solvent-exposed surface area of its fusion partners, and different ions in the Hofmeister series at different concentrations. Despite this body of work, we have found that it remains challenging to predict the LCST behavior of a given ELP in a specific set of conditions, including ions and co-solutes. Moreover, there is ongoing interest in understanding the contributions of colligative and intensive solution properties within the context of ELP LCST behavior. Here, we provide a detailed description of the phase behavior of a polyelectrolytic ELP in different solution conditions and interpret the results considering an integrative, postreductionist perspective. Dynamic light scattering (DLS) serves as our primary technique, providing insights into ELP particles that extend beyond turbidity measurements to offer insight into the intricate interplay of influences on ELP LCST behavior and new avenues for inquiry.