Krejčí was born in Strakonice, Czech Republic and played basketball for the youth academy of Sokol Pisek.[1] At age 14, he joined Spanish basketball club, Zaragoza. In the 2016–17 season, he began playing for Anagan Olivar, the reserve team of Zaragoza, in the Liga EBA.[2]
Professional career
Basket Zaragoza (2017–2021)
On 5 March 2017, at 16 years and eight months of age, Krejčí made his professional debut for Zaragoza against Fuenlabrada. He tied with Sergi García as the second-youngest debutant in club history, behind Carlos Alocén.[2] On 17 April 2020, Krejčí declared for the 2020 NBA draft.[3] In the 2019–20 season, Krejčí averaged 3.2 points in 9.2 minutes per game and was named to the ACB All-Young Players Team.[4] On 25 September 2020, he suffered a season-ending left knee injury in a game against Real Madrid.[5]
On 22 December 2023, Krejčí signed another two-way contract with the Hawks.[15]
On 12 July 2024, Krejčí signed a four-year, $10 million contract extension with the Hawks.[16]