[7][8] He defended Jamat's Leader Abdul Quader Molla at the International Crimes Tribunal in 2013, who was sentenced to death.

[11] Islam, a Supreme Court lawyer, was appointed as the Chief Prosecutor of the International Crimes Tribunal by the government on 7 September 2024.

His appointment was formalized through a gazette notification issued by the law ministry, granting him the status of the Attorney General.

[5][7] Following his appointment, Tajul Islam highlighted the challenges ahead, including handling cases involving high-profile political figures.

He emphasized the complexities involved in gathering, compiling, and presenting evidence and expressed the need for restructuring the tribunal's team by appointing new judges and investigators.