In the ensuing negotiations to form a third coalition government under Chancellor Angela Merkel, she was part of the SPD delegation in the working group on internal and legal affairs, led by Hans-Peter Friedrich and Thomas Oppermann.

In the negotiations to form Merkel’s fourth coalition government following the 2017 federal elections, Lambrecht was part of the working group on financial policies and taxes, led by Peter Altmaier, Andreas Scheuer and Olaf Scholz.

In Merkel's fourth cabinet, she joined the federal government as one of two Parliamentary State Secretaries serving under Finance Minister Olaf Scholz.

On 19 June 2019 it was announced that Lambrecht would succeed justice minister Katarina Barley on the 1 July 2019, after the latter moved to Brussels to serve in the European Parliament.

[7] During Lambrecht's time in office, German authorities fined Facebook 2 million euros for under-reporting complaints about illegal content on its social media platform in breach of the country’s law on internet transparency.

[8] In December 2019, she proposed a law requiring internet service providers like Gmail or WhatsApp to handover personal data including passwords upon request.

[14] Early in her tenure, Lambrecht and Germany as a whole were severely criticized for their very sluggish response to requests by Kyiv for military aid in face of the threatening Russian invasion.

[16] In early February Lambrecht oversaw efforts to send up to 350 more German troops to Lithuania, reinforcing a German-led NATO Enhanced Forward Presence combat unit deployed there to deter a Russian attack on the Baltic states.

[14] With regard to the air force, the ministry quickly announced plans to purchase 35 Lockheed Martin F-35 Lightning II fighter jets to replace its Panavia Tornado.

[19] In March 2022, Lambrecht was openly criticized by Mykhailo Podolyak, adviser to the Ukrainian president, for saying that "NATO won't intervene in the Russo-Ukrainian War".

[25] In August 2022, Lambrecht sent 13 military aircraft to join the Exercise Pitch Black in Australia, the German Air Force’s largest peacetime deployment, underlining Germany’s increased focus on the Indo-Pacific amid rising tensions with China in the region.

[27] In a widely criticized New Year's Eve address she stated that the 2022 Russian invasion of Ukraine has led to "a lot of special experiences" and a chance for "many encounters with great and interesting people".