Energy harvesters like piezoelectric nanogenerators can convert mechanical energy into electrical energy without any external voltage source. However, the discontinuous supply of mechanical energy is the major lacuna in such systems. All-in-one system can harvest mechanical energy, convert to electrical energy and simultaneously store in a single integrated system without external power supply. Herein, bio-waste fish scale (FS) is used as piezoelectric separator in self-chargeable supercapacitor device (SCSD). The SCSD exhibits energy and power density of ∼42 W h kg−1 and 2 kW kg−1, respectively with cyclic retention of ∼80 % after 10,000 continuous galvanostatic charge-discharge cycles. SCSD can be charged up-to ∼350 mV from its open circuit potential of ∼115 mV under continuous human finger imparting within 20 s. The self-charging mechanism is discussed considering Maxwells law, Hooke's law and Poynting theorem. A maximum voltage of ∼448 mV is reached upon continuous finger press and release. The voltage output of SCSD by finger impacting is almost stable even after 5 months. Six such devices connected in series are capable to power a LED light only by pressing manually without any rectification circuit. This finding opens up a new paradigm for the development of a self-chargeable supercapacitor device.