Novel hydrogels with tunable mechanical properties similar to human soft tissue have increasing applications in biomedicine, soft robotics, and biocompatible electronics. However, most of these materials require multiple-step fabrication, are not robust, and compromise bioactivity. Thus, aiming to address these shortfalls, herein, we report a versatile hydrogel system with tunable properties and a facile one-pot fabrication process. The hydrogel system is comprised of a hydrogen-bonded hydrophilic polyurethane (HPU) network and a loosely crosslinked copolymer crosslinked with long chain crosslinkers and decorated with succinimide groups. The active succinimide sites conjugate to proteins, such as bovine serum albumin as a model protein, providing additional biocompatibility and controlled release of growth factors and peptides. The interpenetrating nature of this hydrogel system provides a high degree of freedom over mechanical and physical properties by adjusting the ratio of networks and the composition of the second network. Through this process, a library of biocompatible hydrogels with stiffness ranging from 1 to more than 200 kPa was developed. Moreover, it was found that the succinimide groups impact the degree of crosslinking and contribute to the controlled release of peptides.