Controlled delivery of growth factors is critically important in directing tissue regeneration, which motivates the development of customized biomaterials for growth factor provision. Following the lead of the natural extracellular matrix, reversible adsorption of growth factors to material building blocks possessing cytokine affinity is considered an advantageous design principle for that purpose. Based on this concept, a biohybrid hydrogel composed of star-shaped poly(ethylene-glycol) (starPEG) and heparin was developed. The presence of starPEG determines the structural and mechanical network characteristics, while heparin enables the reversible immobilization of growth factors and the covalent binding of cell adhesive peptides. By varying the molar ratio of starPEG to heparin during gel formation, different hydrogel types with gradated physical properties but constantly high heparin content were obtained. We show that the matrices bind and release various heparin-affine cytokines, including vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF-2), bone morphogenetic protein 2 (BMP-2) and stromal-cell derived factor-1α (SDF-1α), independently of the network characteristics. Moreover, the material could be used for the parallel provision of different growth factor combinations over a broad range of concentrations. The cytokine delivery by modular starPEG-heparin hydrogels was proven to be effective in different in vitro and in vivo experiments, suggesting that the hydrogel platform will be an important tool in advancing regenerative therapies.