Nature has achieved controlled and tunable mechanics via hierarchical organization driven by physical and covalent interactions. Polymer peptide hybrids have been designed to mimic natural materials utilizing these architectural strategies, obtaining diverse mechanical properties, stimuli responsiveness, and bioactivity. Here, utilizing a molecular design pathway, peptide polyurea hybrid networks were synthesized to investigate the role of architecture and structural interplay on peptide hydrogen bonding, assembly, and mechanics. Networks formed from poly(beta-benzyl-L-aspartate) poly(dimethylsiloxane) copolymers covalently cross-linked with a triisocyanate yielded polyurea films with a globular-like morphology and parallel beta-sheet secondary structures. The geometrical constraints imposed by the network led to an increase in peptide loading and similar to 7x increase in Young's modulus while maintaining extensibility (similar to 160%). Thus, the interplay of physical and chemical bonds allowed for the modulation of resulting mechanical properties. This investigation provides a framework for the utilization of structural interplay and mechanical tuning in polymer peptide hybrids, which offers a pathway for the design of future hybrid biomaterial systems.