Alexander Declercq (1998) began his piano studies at the Stedelijk Conservatorium in Bruges under the guidance of Ann Roelens (and later Timur Sergeyenia). Two years later, he embarked on his clarinet studies with Filip Demeyer (later with Vlad Weverbergh and Geert Baeckelandt). He continued his musical journey at the Royal Conservatory of Brussels in the classes of Jan Michiels and Benjamin Dieltjens. After achieving both of his master's degrees Summa cum Laude, he further specialized at the Hochschüle für Musik und Tanz in Cologne under the tutelage of Sheila Arnold. There, he also received coaching in chamber music from Robert Kulek and Anthony Spiri. Additionally, he obtained his bachelor's degree in music notation from KCB.

From a young age, he has been involved in various national and international competitions. He won the 'VLAMO Competition', secured 2nd place in the 'Concours international de Piano de Liège', 2nd place in the 'Concours International Andrée Charlier', 2nd place in the 'Karlrobert Kreiten Klavierwettbewerb', and 3rd place in the 'Stephan De Jonghe Competition' in Aalst. He has also received awards in the 'Cantabile Piano Competition'. This allowed him the opportunity to perform in various venues throughout Belgium. In November 2021, he was awarded a scholarship from the 'Stichting Nany Philippart' to support his studies. The following year, he received the Horlait-Dapsens Prize for his achievements at school. Besides pursuing his solo career, Alexander is equally passionate about chamber music and orchestral music. This has afforded him the opportunity to perform in Hungary, France, California, the Netherlands, the United Kingdom, Germany, Spain, and more. He has played in various prestigious venues both in and outside of Europe, such as Wigmore Hall, Concertgebouw Bruges, De Singel, Copley Symphony Hall, Bozar, Flagey, and others. Alexander has performed at several festivals, including the 'Klavier-Festival Ruhr', 'Midis-Minimes', the 'Gentfestival van Vlaanderen', 'Arte Amanti', 'FazioliFest', 'Konvooi Kunstenfestival', 'Zomer van Sint-Pieter', 'Muziekzomer van Gelderland', 'KlaraFestival', and more.

In addition to the excellent guidance of his teachers in Brussels and Cologne, Alexander has also received lessons from numerous influential educators from around the world. Among them are renowned names such as Jos Van Immerseel, Abdel Rahman El-Bacha, Klaus Hellwig, Claire Chevalier, Johan Schmidt, Sergei Edelmann, Lukas Vondracek, Etienne Rappe, David Breitman, André De Groote, Lucas Blondeel, Markus Groh, Fabio Bidini, Gottlieb Wallisch, Claudio Martinez-Mehner, Edoardo Torbianelli, Olga Kern, Boris Berman, Aleksandar Madžar, Hans Ryckelinck…

In the fall of 2021, he co-founded the Young Musicians Bruges (YMB) collective with some friends. With this collective, he seeks ways to bring classical music to diverse audiences without compromising on the complexity or popularity of the music. For similar reasons he is also part of the nonprofit organization Yehudi Menuhin Live Music Now Köln e.V., who reaches out to people who, due to their circumstances, are unable to attend concert halls. Alexander is the clarinetist in Trio Brisk and Som'Ensemble and the pianist of the Cortenbach Trio. Additionally, he frequently performs in duo with Emile Souvagie and Veronique De Raedemaeker.