 Hejnová won the first round of the Women's 400 m Hurdles at the 2012 Summer Olympics.On 8 August 2012 Hejnová won the bronze medal in the finals.Hejnová won Diamond League races over 400 m Hurdles in Shanghai (53.79), Eugene (53.70), Oslo (53.60), Paris (53.23 NR), and London (53.07 NR).