Gabriel Hollander is classicaly trained in conducting, vocal coaching and piano. His musical mentors include Daniel Blumenthal, Boyan Vodenitcharov (Royal Conservatory of Brussels), Markus Tomas (Leipziger Hochschule Für Musik und Theater), Rodolfo Saglimbeni (Sherborne Summer School) and Kenneth Kiesler (Michigan University). Gabriel is laureate of several competitions, for example Jong-Tenuto, Cantabile, Rotary Brueghel and Dexia Classics.

His conducting debut was in 2014 in a Mozart piano concerto, with Severin von Eckardstein as soloist. Since, he has worked with numerous orchestras and choirs, among others the VUB Players (Belgium), the Choir and Orchestra of the Minimes, the Carloo Cantores choir (Belgium), the A Chantar choir (Belgium), the Orion Orchestra in Aberystwyth (Wales), the Berlin Sinfonietta (Germany), the Pazardzhik Symphonyc Orchestra (Bulgaria) and the Michigan University Students Orchestra (USA). 

As singing coach, Gabriel regularly works with international singers such as Sarah DefriseGéraldine Naus, Marco Zelaya, Astrid Defauw and Emmanuel Junk.

Since September 2017, Gabriel is the music director and principal conductor of the Philharmonic Orchestra of Uccle. Furthermore, starting from September 2018, he also took the role as music director and principal conductor of the German Embassy Choir of Brussels and the Brussels Madrigals Singers.