Bernstiel studied political science and sociology at the Martin Luther University of Halle-Wittenberg until 2010 graduating with a Magister Artium.

From 2010 to 2017, he worked at the multimedia centre Mitteldeutsches Multimediazentrum Halle (Saale), initially as PR officer and later as head of communications.

While working, Bernstiel took a compact study course at the German Press Academy (depak) from 2010 to 2012, graduating with a degree in communication management.

On 24 September 2017, Bernstiel was elected to the German Bundestag as a direct candidate with 27.1% of all first votes in the Halle constituency and northern Saale district going to the CDU.

He is working to keep the participation of Chinese companies in the expansion of the 5G mobile network as low as possible to prevent manipulation or intervention in the national security of Germany.

Alongside these key areas, Bernstiel also works on the topics of counterintelligence, international police missions, and the digital radio network for German security authorities and organizations.