On 14 May 2021, Hersant was charged after a raid by counter-terrorism police at a house in the Melbourne suburb of Rowville.[4] Hersant and a co-offender, Thomas Sewell (neo-Nazi), were charged after an attack on three hikers in Victoria's Cathedral Range.[5] Up to 15 other masked men attacked two passengers in a car and smashed windows. On 1 August 2023, Jacob and a co-offender, Thomas Sewell pleaded guilty to one charge of violent disorder.[5] On 27 October 2023, Hersant and a co-offender were spared further jail time and sentenced to time already served.[6][7] Following the initial sentence, prosecutors appealed claiming that the sentencing was manifestly inadequate.[2]
Following being spared of further jail time, in relation to their attack of hikers,[6] Hersant performed a Nazi salute outside of court.[8][9] Hersant subsequently became the first person charged with making Nazi gestures in public, under new Victorian state laws.[3][10]
In July 2024, Hersant and 40 masked men stormed a Melbourne train station, carrying a banner which stated "Mass deportations now".[10] Following the event Hersant was arrested for "grossly offensive public conduct".[10]