Following a standout season with Freiburg, Kruse signed for Borussia Mönchengladbach on a four-year deal in April 2013. He made his debut for the club in Gladbach's loss to 3. Liga side Darmstadt 98 in the first round of the DFB-Pokal on 4 August 2013. He managed to score his first goal for the club on 17 August, firing in Gladbach's first goal in a 3–0 home victory over Hannover 96. Kruse continued his scoring form on 31 August, netting Gladbach's third goal of a 4–1 home victory over his former club Werder Bremen.
Kruse received his first call up to the senior squad for a friendly against Ecuador on 29 May 2013 in Boca Raton, Florida. He provided the assist for Lukas Podolski's second goal of the match before being substituted for Dennis Aogo in the 79th minute. The match ended with a 4–2 victory. Kruse scored his first goal for the national team in his second cap, scoring Germany's second goal in a 4–3 defeat to the United States in Washington, D.C. on 2 June, a game which celebrated 100 years of the United States Soccer Federation. Despite Kruse's successful league campaign with Gladbach, he was omitted from the 30-man preliminary squad for the World Cup in Brazil.