[1] Markert joined the Nazi Party in 1931 and, on 12 October of that year, he was promoted to Deputy Director of the employment office in Bremen.

After the Nazis seized power at the national level, they instituted a policy of Gleichschaltung (coordination) by which they sought to assert their control over all the German Länder.

[3] Reich Interior Minister Wilhelm Frick appointed Markert as the Reichskommissar for Bremen and entrusted him with authority over the police.

In his new role, on 11 March, he appointed individual Spezialkommissare (special commissioners) to monitor the official actions of the few senators still remaining in office.

On 16 June, Markert also secured a position in the Reich Ministry of Labor as the Trustee of Labour for the Lower Saxony economic region.

He saw this as important for the Bremen economy to retain its independence, by avoiding a joint governorship with the much larger seaport of Hamburg, which its Bürgermeister Carl Vincent Krogmann was advocating.

Additionally, the Bürgerschaft of Bremen, the state's legislative body, was reconstituted on 5 April 1933 on the basis of the recent Reichstag election, giving the Nazis and their conservative ally the German National People's Party a working majority of the seats.

[7] From March 1934 onward, there were increasing conflicts between Markert and Röver, especially when the latter sought to have Bremen become a Regierungsbezirk (government district) of Oldenburg.

This eventually brought about the end of Markert's political career, as he was removed from his executive offices in Bremen on 23 October 1934 and was replaced by Otto Heider [de].