Bert Willemsen was born on November 22, 1973 in Haarlem and studied HaFaBra conducting with Jan Schut (Bachelor's degree, 1997) and Classical Trombone with Jaap Dekker (Teaching musician, 1999) at the conservatory of the Alkmaar University of Applied Sciences.

In 2013, Bert obtained his Master's degree in HaFaBra conducting at the Royal Conservatory of The Hague with Alex Schillings.
As a low brass teacher, he was associated with the Opmeer Music and Dance School for many years.

He conducts the following orchestras: Music Association Winnubst Den Helder (concert band), KLM orchestra Badhoevedorp (concert band), Harmoniecorps Tuindorp Amsterdam, Koninklijk Zeister Harmonie Muziekgezelschap, Fanfarecorps Erica Austerlitz and works as a trombonist, tubaist, guitarist and bass guitarist.
Bert has worked with several artists including: Henk Westbroek, Margriet Eshuijs, Cor Bakker, Guus Meeuwis, Petra Berger, Tony Neef, Jamai, Do, Belle Perez, Charly Luske, Anita Meyer, Ellen ten Damme, Karin Bloemen, Ruud Breuls, Berget Lewis, Stanley Burleson, OG3NE, Dennis van Aarssen, Shirma Rouse and conducted various musical productions and CD recordings.

In addition to conducting and playing, Bert is also involved in arranging compositions for wind and brass orchestras, a number of which have been published by music publisher Bronsheim in IJsselstein and Molenaar Edition in Wormerveer.