Bovine serum albumin (BSA) emerged as a potential bioprotein in the sensing field. Understanding the interactions of BSA with the analyte biomolecule has not been much reported. Herein, we report the functionally modified BSA (f-BSA) and its consecutive adsorption onto DNA for the ultrasensitive protein sensing. The DNA-modified f-BSA (DNA@f-BSA) composite was further characterized by using scanning electron microscopy, X-ray diffraction and Fourier transform-infrared spectroscopy. Obtained results demonstrated excellent composite formulation due to electrostatic interaction/binding intercalation and provided promising scaffold for protein biosensor. The as-prepared DNA modified f-BSA (DNA@f-BSA) based biocomposite can be used as a selective probe for the detection of BSA by recording square wave voltammetry signals. The sensitivity of the hybrid biosensor significantly improved the BSA detection over a wide concentration range from 1 × 10⁻²⁰ g ml⁻¹ to 1 × 10⁻⁴ g ml⁻¹ with a detection limit of 2.18 × 10⁻²¹ g ml⁻¹. Thus, the results have revealed the promising biosensor interactions which pave the way for the sensitive protein detection.