Formed at Genk, he spent most of his professional career in Germany with 1899 Hoffenheim, Werder Bremen (loan) and VfL Wolfsburg, making over 200 Bundesliga appearances.
Casteels made 37 appearances for Belgium up to under-21 level.
Casteels was signed by VfL Wolfsburg from TSG 1899 Hoffenheim in January 2015, but spent the first six months of the three-and-a-half-year contract on loan at Werder Bremen.
1992
Koen Casteels (born 25 June 1992) is a Belgian professional footballer who plays as a goalkeeper for Bundesliga club VfL Wolfsburg and the Belgium national team.
2013
He was first called up for the senior team in 2013 and was part of their squad that came third at the 2018 FIFA World Cup.
Casteels was developed at K.R.C. Genk where he was a teammate of fellow goalkeeper Thibaut Courtois.
He was initially regarded as better than Courtois, but while he and several of the club's other goalkeepers were injured, Courtois broke into the team.
Casteels was first called up to the senior Belgium team in May 2013.
2014
He was going to be part of Belgium's 2014 FIFA World Cup squad but failed to recover from an injury and was replaced by Silvio Proto and then Sammy Bossut.
2015
He played for Wolfsburg in the 2015 DFL-Supercup, saving from Xabi Alonso in the penalty shootout as his team won after a 1–1 draw.
2017
When Diego Benaglio left Wolfsburg in June 2017, Casteels signed a new three-year contract with the club and was given the number 1 shirt.
He appeared in all of the club's 34 Bundesliga matches during the 2017−18 season.
On September 2, 2023, Casteels announced that he will leave at the end of the 2023−24 Bundesliga season.
2018
Manager Roberto Martínez often chose four goalkeepers in his international selections, and as the 2018 FIFA World Cup only permitted three, Casteels battled with Matz Sels for the final space behind Thibaut Courtois and Simon Mignolet.
He was eventually chosen for the final 23-man squad to go to Russia.
2020
Casteels made his full international debut on 8 September 2020, in a 5–1 win over Iceland for the UEFA Nations League.
