New materials and devices for bioelectronics have emerging applications in healthcare monitoring and disease diagnostics. Hydrogel‐based sensors face great challenges in achieving desirable synergistic performances including intrinsical electron conduction, bacterial resistance, anti‐swelling property, and adhesion to tissues. To address current bottlenecks, poly(Cu‐arylacetylide) derived hydrogels are developed for the first time that demonstrates all these above intriguing performances as a result of the special Cu‐arylacetylide backbone. The hydrogels show the capability of recording electrocardiogram (ECG), electromyogram, implantable epicardial ECG, and transmitting neural signals. Furthermore, the Cu (I) in polymer chains can be substituted by other metal ions such as Au (I), which can create numerous new materials with intriguing performances. This study not only creates a new research field of hydrogels but advances design concepts for implantable electrodes to record bio‐electron.