Liga for Sparta's reserve team, Kadeřábek went out on loan to Czech First League side Viktoria Žižkov.

[6] Kadeřábek joined up with the Czech under-21 team for the first time ahead of a match against the Netherlands in August 2013.

[7] He represented the Czech U21 team at the 2015 UEFA European Under-21 Championship, and scored the opening goal of the tournament in a 1–2 loss to Denmark at the Eden Arena in Prague.

[9] He scored his first goal for the Czech Republic in a 2–1 UEFA Euro 2016 qualifying win against Iceland on 16 November 2014.

[10] In June 2016, Kadeřábek was included in coach Pavel Vrba's 23-man squad for the UEFA Euro 2016 in France.