Soak n' Boost: A universal strategy to manufacture hybrid double-network hydrogels with eminent mechanical properties is developed by postformation of the chitosan microcrystalline and chain-entanglement physical networks via simple treatment of the chitosan composite hydrogels using alkaline and saline solutions. The strategy may open an avenue to fabricate multifarious double-network hydrogels for promising applications in antifouling materials, drug delivery, and tissue engineering.