Born in 1978 in Tomaszów Mazowiecki, composer and music theorist. He graduated with honours in music theory (2005, class of Ryszard Daniel Golianek) and composition (2008, class of Bronisław Kazimierz Przybylski) from the Academy of Music in Łódź. He also studied electronic music with Krzysztof Knittel. In 2012 he obtained his DMA degree in composition under the supervision of Zygmunt Krauze.

In 2017, his brut represented Polish Radio and won the main prize (selected work) at the International Rostrum of Composers in Palermo(its world premiere was recorded at the inaugural concert of the 57th Warsaw Autumn Festival in 2014). He was nominated for the Coryphaeus of Polish Music as Personality of the Year (2017) and for Polityka’s Passport Award (2018). Zagajewski has won prizes in competitions for composers such as BMW Crash! of the Zachęta Contemporary Art Association in Szczecin (twice), the 48th and 50th Tadeusz Baird Competition for Young Composers, and the 3rd Grażyna Bacewicz International Composers’ Competition in Łódź, among others. In 2014 his Stabat Mater was nominated for the Polonica Nova Award in Wrocław. His other accolades include the Gloria Artis Bronze Medal for Merit to Culture, the President of Łódź Award, and twice the Łódź Eureka Prize.

His works have been performed at festivals such as the Donaueschinger Musiktage, MaerzMusik, Warsaw Autumn, Musica Polonica Nova, Festival of Premieres – Polish Modern Music, Sacrum Profanum, KODY / CODES Festival of Traditional and Avant-Garde Music, Poznań Music Spring, New Music Days, Ad Libitum, Audio Art, NeoArte – Synthesizer of Arts, as well as Cricoteka Centre for the Documentation of the Art of Tadeusz Kantor, among others. In 2016 he was invited to take part in the MusMa European Broadcasting Project. In 2024 he was composer-in-residence at the Musica Polonica Nova festival. His works have been commissioned by the Südwestrundfunk (for the Donaueschinger Musitage), Darmstadt International Summer Courses for New Music, and NOSPR. He has cooperated with artists such as Arkadiusz Jakubik, Dominik Połoński, Agata Zubel, Łukasz Długosz, Agata Kielar-Długosz, Gośka Isphording, Paulina Wycichowska, Zorka Wollny, Piotr Stasik (their joint project Opera about Poland was nominated for the Eagles Polish Film Awards in 2019 in the category of documentary films) as well as ensembles such as Bang on a Can All-Stars, OMN Ensemble, Kwartludium, Kwadrofonik, the Silesian String Quartet, Spółdzielnia Muzyczna Contemporary Ensemble, Hashtag Ensemble, Arte dei Suonatori, flow unit, Polish Cello Quartet, Small Instruments, Hańba! and Radical Polish Ansambl.

He has also created many works and projects for amateur musicians, including Nature Morte for 24 PCV tubes (2013), blockhaus C for sound objects (2015), La Citta futurista for a 16-piece amateur ensemble and orchestra (a Łódź Philharmonic commission for the centenary of its orchestra, 2015), and March for amateur choir and orchestra (2017). His work includes rock music, lectures and workshops on20th and 21st-century music, as well as ear training (he was, among others, a jury member at the mYear Festival of Musical Imagination at the Wrocław Academy of Music). He is also the author of a cycle of online broadcasts What’s It About? Music Created Today, produced in 2021 for Łódź Philharmonic. Zagajewski is a faculty member of the Bacewicz University of Music and the Stanisław Moniuszko Music School Complex, both in Łódź. He is a member of the Warsaw Autumn Repertoire Committee.

Selected works: Glassmusic-Motet for chamber ensemble and audio track (2007), TR13 for accordion and audio track 2005–14), Birds for accordion, synthesizer and audio track (2008), Leaves for chamber ensemble (2008), unhum for symphony orchestra (2009), ChronophotographicScenes, ballet (2011), Oratorio for Orchestra and Warsaw Citizens’ Choir, concerto / performance (with Anna Szwajgier and Zorka Wollny,2011), Stabat Mater for four mixed choirs and instrumental ensemble (2012), canto for 16 musicians (2012), EC 14 for four PVC tubes (2012),brut for cello and early music ensemble (2014), Canzona for five cellos (2014), Mechanotexture for chamber ensemble (2015), Woodcuts for chamber ensemble and audio track (2015), circulatio for accordion, quartertone accordion and orchestra (2015), sculpture (from the way of the cross) for four cellos (2016), Steel-Eyed for two punk rock voices and chamber ensemble (2016), Opera about Poland (2016), Modulor for chamber ensemble (2017), Composition arithmétique for piccolo and monophonic track (2017), Holy God, Holy and Mighty for male voice and chamber orchestra (2018), chanson solide for two marimbas (2019), Constructivist Songs for female voice with percussion and string quartet (2019), LA MER / watch?v=y1RpVZNSw6k for chamber ensemble (2019), ricercar for eight cellos (2019), POWERBIT! for voices, toy pianos and synthesizer, to excerpts from Dorota Masłowska’s Other People (2019), Madrigal Music for six-part choir and six instruments (2019),Concerto for two Flutes and Orchestra (2019), EUR (post cold wave new synth romantic punk) for chamber ensemble (2020), und nur dieser Wind for orchestra (2021), 7 for chamber ensemble (2021), Tired with all these, for restful death I cry for chamber orchestra and video (2022), Danses polonaises for two pianos, two synthesizers, and audio track (2022), [...]! for chamber ensemble and audio playback (2023), Tree of Life for female voice and chamber ensemble (2023), LOVE LOVE LOVE LOVE for pianist, percussionist and audio playback (2023), the sun is gone for chamber orchestra (2024), 4 songs to poems by Chava Rosenfarb for male voice and chamber ensemble (2024), crash 24 for contrabass clarinet and audio track (2024), 5 Pictures of Death for two microphone accordions (2025), It was October, it was still dark for chamber ensemble (2025).