Following the 2017 state elections in North Rhine-Westphalia, Wittke was part of the Armin Laschet’s team in the negotiations between CDU and Free Democratic Party on a coalition agreement.

In the negotiations to form a coalition government under the leadership of Chancellor Angela Merkel following the 2017 federal elections, Wittke was part of the working group on transport and infrastructure, led by Michael Kretschmer, Alexander Dobrindt and Sören Bartol.

With the formation of the fourth Grand Coalition, it was announced that Wittke would move to the position of Parliamentary State Secretary at the Federal Ministry of Economic Affairs and Energy under Minister Peter Altmaier.

[3] Together with Roland Heintze, Daniel Günther, Andreas Jung, David McAllister, Nadine Schön and Antje Tillmann, Wittke co-chaired the CDU’s 2018 national convention in Hamburg.

[8][9] Ahead of the Christian Democrats’ leadership election in 2018, Wittke publicly endorsed Annegret Kramp-Karrenbauer to succeed Angela Merkel as the party's chair.