Appointed by President William Ruto and confirmed through parliamentary vetting, Kanja took office on September 19, 2024.

Over his career, he rose through various ranks, holding prominent roles, including deputy inspector general of the Kenya Police Service and commandant of the General Service Unit (GSU), where he served for five years.

[2][3] In September 2024, Kanja was nominated by President William Ruto to serve as the inspector general of the National Police Service.

His nomination was unanimously confirmed by the Kenyan Parliament after he successfully completed the vetting process.

During the confirmation hearings, legislators cited his extensive experience and commitment to the police service as key qualifications for the role.