Koukal started playing badminton in 1993, at a club owned by his father in Hořovice, and made his debut in the international tournament in 2000.

[3] In 2010, Koukal was diagnosed with testicular cancer and underwent a successful therapy.

[1] In July 2012, Czech Olympic Committee announced selection of Koukal for flag bearer of Czech team at the 2012 Summer Olympics in London, citing him as an example of sport role in recovery from a grave illness and of return to competition at top level.

In May 2016, Czech biathlete Gabriela Soukalová became his spouse;[7] they divorced in late 2020.

He made his third appearance at the Summer Olympics through the Tripartite Commission Invitation.