Johan Treichel was born in the Canton of Neuchâtel, Switzerland. After beginning his professional studies in Catherine Courvoisier's piano class at the La Chaux-de-Fonds Conservatory, he followed the teaching of Paul Coker and Marc Pantillon at the Haute École de Musique de Neuchâtel (Master of Interpretation and Master of Teaching). At the same time, he studied composition with Michael Jarrell and Luis Naón at the HEM in Geneva, then with Marco Stroppa at the Hochschule für Musik und Darstellende Kunst in Stuttgart. Finally, he completed his training in the organ class of Pascale Van Coppenolle at the Haute École des Arts in Bern, obtaining a Diploma of Advanced Studies then a Master of Advanced Studies.

He followed the master classes and workshops of Eric Gaudibert, Helmut Lachenmann, Matthias Pintscher, Tristan Murail, Henri Dutilleux, Brice Pauset and Martin Matalon (composition), the Aviv Quartet, the Wanderer Trio, Jean Piguet, Sergey Ostrovsky and Omar Zoboli (chamber music), by Michel Kiener, Florence Malgoire and Serge Saïtta (early music). During his years of study, he obtained several distinctions as a pianist: first prize at the Friborg Contemporary Music Competition in 2005 and 2007, first prize at the Racconiggi Competition (Italy) in 2007, Faber Music Prize in 2005, Prize Miéville-Hory in 2007, third prize at the Frédéric Chopin Competition in Rome (Italy) in 2006. He was also a grant recipient of the Jean Tanner, Lyra, Fritz Gerber, Irène Dénéréaz and Friedl-Wald foundations.

A pianist with a passion for chamber music, he shares the stage with several performers in groups ranging from duos to large ensembles. He is notably a member of the Gamajun Trio with cellist Marina Zinsstag-Cotallo and violinist Jeanne-Lise Treichel, a group with which he has given numerous concerts in Switzerland and France since 2014. He is also harpsichordist of the Ensemble Hexacorde and pianist of the Neuchâtel Symphony Ensemble. In a completely different register, he collaborates with the artist Swann Thommen within the electronic music duo ILS.

Since 2021, he has played the keyboards of the organ of the collegiate church of Saint-Imier, in the Bernese Jura. Its accompaniment of the liturgy gives space to various music: baroque and romantic organ repertoire, piano, electronic music and, above all, improvisation. In the wake of his appointment, he founded the Association Musique à la Collégiale, which offers numerous concerts to audiences in the region.