This work characterizes the gelation, phase equilibria, and drug delivery of elastin-mimetic triblock (EMT) hydrogels in aqueous solution. Elastin-mimetic triblock polypeptides were expressed in recombinant Escherichia coli with a sequence based on the key elastin repeat sequence VPGVG (valine-proline-glycine-valine-glycine) and are constructed as BAB block copolymers. The B-blocks are more hydrophobic than VPGVG, while the A-blocks are more hydrophilic. The gel re-liquefies upon cooling. These hydrogels are also ionically and thermally responsive (i.e. they undergo large volume changes as a result of these responses). Understanding the secondary structure evolution of polypeptide chains during gelation is important to the field of biomaterials. The hydrogel network was shown to form by conversion of polyproline-II-like structures to intermolecular beta-sheet structures. However, increase in beta-sheet structures was modest (15-40%) compared to the macroscopic event of gelation. Type II beta-turns were present with beta-sheet structures in isolated B-blocks, implying they also stabilize the network. Sol-gel temperature transitions (gel points) were shown with DSC (differential scanning calorimetry) to decrease (21-16°C) with increasing concentration (2.5-12.5 wt%). The enthalpies of gelation were 2200-2900 kJ/mol and increased slightly with concentration from 0.5-12.5 wt%. Post-gelation, the network swells to a stable equilibrium in excess solution. A temperature-composition phase diagram was developed to consolidate the data for thermal gelation and thermal responsiveness of the EMT-water system. These hydrogels exhibit lower critical solution temperature behavior near 15°C with a two-phase region containing a very dilute sol fraction (0.001 wt%) in equilibrium with the gel. Significant concentration dependence of the swelling degree implied the crosslinking density increased with synthesis concentration based on the hypothesized ?-turn content in A-blocks increasing as well. As synthesis concentration increased, so did the thermal responsiveness. This thermal responsiveness was exploited to accelerate the release of solutes from the network. The release of three solutes, with a molecular weight range of (100-45000 Da) from 20 wt% EMT hydrogels was Fickian and diffusion coefficients were on the order of 10^-8 to 10^-6 cm2/s. The release rate was increased up to 150% with ovalbumin (MW = 44600 Da) at 50°C compared to its release at the polymer synthesis temperature (25°C).