He first started doing voice-overs as a teenager and has been working in this profession since the inception of the Telewizja Polska. In the 70’s, he read the dialogue lists during the cult film review, Konfrontcje. A decade later, with the boom of films distributed on video tapes, Tomasz Knapik has become a sought after voice-over provider for the films on VHS. He read everything, from transcripts of the outstanding works of the cinema to B movies and even pornographic features. He was a regular employee of such Polish distributors as Artvision, Best Film, Imperial, ITI Home Video, NVC VIM, or Vision. Tomasz Knapik also provided voice-over in the renowned Polish Film Chronicle - film magazine documenting important events in Poland of the time.
In the 90’s, he was providing voice-overs on the regular basis for the Polsat and Polonia 1 networks, whereas, in the past decade, worked for Tele 5 and TVP1 (the "Re:akcja"). In 2008, he recorded voice announcements for public buses in Warsaw City. He was selected from among many candidates, including Daniel Kondraciuk, Marcin Sanakiewicz, Jacek Sobieszczański whether Janusz Szydłowski. Tomasz Knapik recorded around one thousand seven hundred announcements.
Since September 2010, he has been the narrator in the radio novel "Dom nad wysypiskiem," broadcasted on the RMF FM. In addition to the transcripts for feature films, Tomasz Knapik also reads lines in commercials.