This study proposes a detailed biomechanical model of the human head to study the effect of non-penetrating (blunt) head impacts of different durations on intracranial organs. A patient-specific high biofidelity three-dimensional finite element human head model is developed from the magnetic resonance imaging (MRI) data and segmented into five volumes namely, skull, cerebrospinal fluid (CSF) with ventricular system, cerebrum, cerebellum, and brain stem and each segment is assigned with appropriate material properties. The model validated against the impact experiment based on human cadaver is used to perform simulation with a range of blunt impact durations and biomechanical analysis is performed by investigating the maximum intracranial pressure (ICP) and von Mises stress distribution across the brain. The probability of loss of consciousness and tissue damage is studied based on the ICP and von Mises stress values. The coup and contrecoup phenomena is also studied with the localization, extension and, intensity of tissue damage based on the injury tolerance criteria present in the literature. © 2021, Springer Nature Singapore Pte Ltd.