Marie Nečasová was born in Prague, Czech Republic. Her first composition studies were at the Conservatory of Jaroslav Ježek, after a failed attempt to study at the Academy of Fine Arts. She finished her bachelor degree in Theory and Practice of Ancient Music –  harpsichord with Monika Knoblochová at the Masaryk University, Brno, during which she went for a study stay at the Helsingin Yliopisto in Finland. Deciding between comparative literature studies and composition, she chose the latter, and went to study at the APBU in Linz with Hannes Löschel. During this time she was fortunate enough to experience studying at the CNSMD in Lyon with David Chappuis. She also attended a few courses in musicology in Prague and studied book graphics at VOŠ Hellichova – both experiences have helped her in pursuing her current master’s studies in Music Publishing at the Academy of Performing Arts in Prague, where she focuses on new possibilities of publishing contemporary music. She is interested in visual aspects of composition and how notation a graphics influence performances. In her compositions, she also takes a „visual“ approach; she strives to connect sound textures with strings of voices and melodies – watercolour abstractions with graphic lines.

Her compositions have been performed at festivals such as Brucknerfest (Rewriting Rott, 2021), Leicht über Linz (2020, 2021), Hortus Musicus or Festival Présence Compostrices. She collaborated with ensembles such as Ensemble Delirium, for which she wrote the composition TMY (2021, pr. in Basel); Ensemble les Émissaires (Lumières 2022, pr. in Toulon); JIM Chamber orchestra (réflexions, 2022, pr. in Linz), Ostravská banda (Over, 2021, pr. in Ostrava). She was selected to participate in a series of masterclasses with the composer Milica Djordjević as a part of the project Let a Master Pitch In by the SONUS Foundation and also a residency programme during the festival Ostrava Days, where her orchestral composition Over was premiered. In May 2024 she collaborated with The Prague City Gallery and Prague Quiet Music Collective, introducing a new composition Otevírání, which is to be seen as a part of the exhibition Album zpomalených obrazů at the Troja Castle. 

Apart from classical composition, she is a proud member of the Early Music social bubble and regularly attends the international summer schools in Valtice and in Holešov, being a laureate of the latter’s interpretation competition (2020, concert at the Hudba Znojmo festival 2021). She has participated in harpsichord master classes and consultations with Tamar Halperin, Shalev Ad-El, Anne-Marie Dragosits, and Daniel Oyarzabal.