[6] Schaub made his debut for Rapid Wien's senior team in the 3–0 Austrian Football Bundesliga win over Sturm Graz on 18 August 2012.

He made his debut for Austria U21 in a 2015 UEFA European Under-21 Football Championship qualification Group 4 1–0 win over Albania U21 on 14 August 2013, coming on as a 76th-minute substitute.

[12] Schaub was named in Austria's senior squad for a 2018 FIFA World Cup qualifier against Wales in September 2016.

His mother is Austrian[14] and his father German, making him eligible to represent either nation internationally.

His father, Fred Schaub, was a professional football player as well, having spent most of his career in the German Bundesliga.