[4][5] He began his professional theatre career in 2004 at the Landestheater Eisenach, even before he actually trained as an actor, and in 2005 he moved to the Hans Otto Theater in Potsdam, where he was a member of the ensemble until 2007.

[1] There he appeared as Jessica in an all-male cast of Shakespeare's tragic comedy The Merchant of Venice, as Spelunken-Jenny in Brecht/Weill's The Threepenny Opera, as Goylbastard Nerron in the world premiere of the children's and family theater play Reckless II - Vivid Shadows by Cornelia Funke and as Kevin "Princess" Marley in the world premiere of the play Fast ganz nah (euer Krieg ist unser Krieg) by Pamela Carter.

[12] In the 2015/16 season he played the role of the impoverished Prince Myschkin in a stage version of Dostoevsky's novel The Idiot in a production by the former Burgtheater director Matthias Hartmann.

[18] In 2017/2018 he premiered the production Jeff Koons, a scenic installation based on the play of the same name by Rainald Goetz, which he created together with Felix Krakow.

[22][23] In 2012 he had an episode role in the ARD crime series Heiter bis tödlich: Akte Ex as a young artist Tobias Krüger.

[25] In November 2015, Kaczmarczyk appeared in the ARD serie In aller Freundschaft – Die jungen Ärzte as Heiko "Ralle" Rallburg.

[26] In the ZDF television thriller München Mord: Wo bist Du, Feigling?, first broadcast in September 2016 he was seen in the role of Niklas Bernhard.

[27] In the 9th season of the crime serie Die Chefin first broadcast from August 2018 he had a leading role as Anton Berger, he embodied the owner of a Munich software and IT company and brother of a psychopathic multiple murderer alongside Franz Pätzold.