Composer, guitarist, sound engineer. Born in 1981, he graduated from the composition class of Zygmunt Krauze and the sound engineering class of Andrzej Lupa at the Fryderyk Chopin University of Music in Warsaw as well as in journalism and political science from the University of Warsaw. He is the director of the Chopin University’s Computer Music Studio. 

His works have been performed at festivals such as Warsaw Autumn, New Music Concerts (Toronto), Polish Modern: New Directions in Polish Music since 1945 (New York), Intersonanzen (Potsdam), Afekt (Tartu), Musica Electronica Nova, Musica Polonica Nova, Musica Moderna, and Audio Art, by ensembles and orchestras such as Musikfabrik, United Instruments of Lucilin (Luxembourg), New Music Concerts Ensemble, Kwartludium, Hashtag Ensemble, Polish Radio Orchestra, Gorzów and Kalisz philharmonics, and the Wratislavia Chamber Orchestra. 

In 2014–15 he was a composer-in-residence at the West Pomeranian University of Technology Academic Choir in Szczecin (as part of the Institute of Music and Dance residency programme). He has won prizes at several competitions including the International Confederation of Electroacoustic Music Prix CIME for #NetworkMusic (2019), the 1st Krzysztof Penderecki International Composition Competition (3rd Prize, 2012), Tadeusz Baird Competition for Young Composers (1st prize forExhorta for tape, 2011 and 2nd prize for Apnea for percussion and pianos, 2010). His Warsaw Music reached the finals of the European Broadcasting Union’s Palma Ars Acustica in 2016. In 2013 he took part in IRCAM Forum Workshops in Paris, and in 2017, in the Composer Collider programme with the Musikfabrik ensemble, resulting in the composition of Theory of Strings for 11 Harry Partch string instruments. He has published two CDs: Thrash Music (Requiem Records, 2018) and Loopovisations (2013). 

He writes both acoustic and electroacoustic music, as well as works for the theatre and film. In his works, Błażejczyk uses instruments he builds himself: objectophones, musical instruments constructed out of everyday objects, whose sound is transformed live, and the gestophone, an electronic instrument controlled by gestures, as well as atypical string instruments. 

He is also active as a concert guitarist, playing new music on the electric guitar and with live electronics. He has appeared in concert notably at the Warsaw Autumn Festival, Sacrum Profanum, Ankunft: Neue Musik, Intersonanzen, Musica Polonica Nova, Musica Electronica Nova, Ad Libitum, Audio Art, and Olympus Jazz Festival. He is a member of the Hashtag Ensemble. He practices improvised music, performing with ensembles such as Mud Cavaliers and Electronisches Glück, with Adam Pierończyk, Agata Zubel, Krzysztof Knittel, and Joëlle Léandre. As a sound engineer, he specialises in recordings and sound projection at new music concerts and sound design for films. He also runs electroacoustic music workshops for children with the use of sound objects. 

Selected works: Schizophrenia for chamber orchestra and tape (2002), MAD–Mutual_Assured_Destruction for chamber orchestra (2007), Seica for ten instruments (2008), Hysteresis Loop for saxophone and tape (2007), Loopovisations .1 / .2 / .3, cycle of improvised works for electric guitar and live electronics (2008–9), Shimmerfor two pianos and two percussion (2009), Hora iudicii for choir and chamber orchestra (2009), Apnea for two percussion and two pianos (2010), Protocol for actor, ensemble and electronics (2010), Exhorta for tape and reciter (2011), Penal Colony for actor and symphony orchestra (2011), Introjection for string orchestra (2012), LoPassHiCut for double bass and live electronics (2013), Guitar Sculptures for electric guitar and live electronics (2013), Bethlehem for choir, soprano, baritone, duduk, percussion, organ and electronics (2013), A Concise History of the Death of Jean Calas for baritone, choir and symphony orchestra (2014), Trash Music for ensemble, voice and objectophones (2014), Particle Horizon for electric guitar, bass guitar, objectophones and live electronics (2014), Warsaw Music for ensemble, voice and live electronics (2015), Music of Strings for electric guitar, piano and string trio (2015), Concerto for electric guitar and string orchestra (2016), Spirits of the Dead for flute, violin and viola (2016), DATA Selfie for three performers and electronics (2017), Angels of Peace for oboe, clarinet, horn and double bass (2017), #NetworkMusic for voice, chamber ensemble and electronics (2017), String Theory for 11 Harry Partch string instruments (2017), Concerto for viola, clarinet, electronics and string orchestra (2018), Étude semi-concrète. Study for Many Strokes on Different Objects for electric guitar, objectophones and electronics (2019), Gestophonyfor gestophone (2019), Aether for flute, clarinet, trumpet, violin, cello, double bass and electronics (2020), The Way of Four Gates for electric guitar, bass guitar, zither, guzheng and electronics (2020), Shine for actor, chamber ensemble and electronics (2020), The Bunker. Fake Opera for four performers, chamber ensemble and electronics (2020–21), Co-Relationsfor voice and gestophone (2021), Stringphony 3.0, sound-and-strings installation (2022).