[1][2] Kaczmarek moved from Poland to Germany at the age of 9[3] and only played on amateur level as an active footballer.
[4] From January 2011, he took charge of the U19's at the club and later a half year for the first team, which he was in charge of until the end of 2011, where he was hired as assistant manager for the Egyptian national team under manager Bob Bradley.
Exactly a year after his appointment, he was relieved of his duties following a poor start to the campaign, with Lechia crashing out of the UEFA Europa Conference League second qualifying round and at the bottom of the league table, with just one point following six games.
[8] On 10 April 2023, Kaczmarek was appointed manager of Eerste Divisie side Den Bosch on a two-year contract.
[10] On 11 June 2024, he joined NAC Breda's coaching staff as an assistant under manager Carl Hoefkens.