Along with the proclamation of the independence of the Republic of Latvia on 18 November 1918, the establishment of a new intelligence and security service was necessary. On 29 July 1919, the State Security Department was established, which was tasked to combat crime aimed at the state constitutional order. On 1 November, 1919, during the warfare in the country, the State Security Department was disassembled and the largest part of its officials were dislocated to the Intelligence unit of the Latvian army. At that time 5th (political) Department of the Criminal Police was formed, which took over the functions of the State Security Department.
On 2 October 1920, the Political Security Department of the Ministry of Interior was established but in the time frame from May 1924 until June 1939, the function of counterintelligence and internal security service was performed by the Political Department of the Ministry of Interior (Political Police Administration of the Security Police Department from June 1939 until June 1940). After the USSR occupation in 1940, more than 90% of the officers of Latvian security and intelligence services were killed or died in the prisons of the Soviet Union.
After the restoration of the statehood, in 1991 the establishment of the system of the intelligence and security services was initiated. In 1991, the Security Service of the Republic of Latvia and the Dignitary Protection Service as well as the Information Department of the Ministry of Interior were established. The Information Department of the Ministry of Interior was responsible for intelligence and counterintelligence activities in order to protect newly established Latvian government.
In 1993, the Information Department of the Ministry of Interior and the Dignitary Protection Service were unified, in the result of which the National Economic Sovereignty Protection Department was established with the aim to provide the security measures crucial at that time.
In 1994, the Law on Intelligence and Security Services was adopted which stipulated the body and legal status of intelligence and security services in Latvia. As a result, the National Economic Sovereignty Protection Department was reorganized and Latvian Security Police was established. With amendments to the Law on State Security Institutions adopted in 2018, from 1 January 2019, the Security Police was renamed the National Security Service.
From 8 November, 2014 until now, Normunds Mežviets is the Director-General of Latvian State Security Service.