Careers within the NSIS are open to Kenya Citizens who are over 18 years old and meet the qualifications required. The wide range of NSIS activities makes it imperative that employees possess a variety of academic backgrounds and abilities.

To operate effectively, the NSIS needs expertise from various professional backgrounds including engineers, lawyers, scientists, communication technicians, and other specialists. When vacancies for employment occur, the Service advertises the posts available in the newspapers. .

Those who posses the required qualifications and submit applications are subjected to a rigorous recruitment process that is aimed at employing the best people for the jobs available. Because of the sensitive nature of security intelligence work, all applicants undergo security vetting, which is carried out by the Service.