From 1995 to 1998, he studied bassoon, piano and music theory at the Art Gymnasium of Ghent. He later on continued studying komposition and orchestration at the Royal Conservatory of Ghent with Lucien Posman, Luc Brewaeys and Godfried-Willem Raes. During this period, he wrote several pieces in various styles and genres, flamboyantly discussed the basics of the craft with musicians from the local music scenes and attended masterclasses with Louis Andriessen and David Rowland in Amsterdam.
In 2002, he became one of the finalists at the Aquarius komposition Contest with his orchestral work Morph (his second symphony). This piece was premiered in Bruges by the Royal Philharmonic Orchestra of Flanders, conducted by Lucas Vis.
In 2003, he graduated at the Conservatory, became connected with the Logos Foundation for experimental and electronic music and developped a steady interest in the M&M Robot Orchestra, established by Godfried-Willem Raes. This Robot Orchestra, in which the forces of Man's musical imagination and the sharp preciseness of Machines fully are combined, has intrigued him for the years to come.
He has written soundtracks for animation movies: in collaboration with stop motion animator Bart Van De Plas, he wrote the music for the short film Haar Haar (Her Hair). After, earlier on, having written part of the soundtrack of Burdenbirds by Lieve Vanderschaeve, this Flemish/German video animator produced a sensual and trippy videoclip on Rouge-Blanc-Dorée, et un ptit peu Noir in her project Zwirrn.

Bradt wrote orchestral/ensemble works for the Spectra Group (Sc(H)ènes), MuSix Ensemble (L'Irréparable-SATAN and Excerpt), Nadar Ensemble (Koest), Junior Orchestra Ars Musica (Talking to the Hand, 'cos the Face didn't want to Hear it Any More), TRIATU Percussion Group (L'Union Fait La Fo/arce), Thelema Trio (Ouattosz/Ouockosz @ Lilith), and Artis Dulcedo. This last group premiered his trumpet concerto Pleurnichard in Bruges, early 2007.

The following years, major commissions popped by when he was asked to collaborate with 8 other komposers to make the soundtrack for the fireworks display at the Gentse Feesten 2008. In 2009 he was invited to write a composition for the celebration of '40 Years of Gentse Feesten bij Sint-Jacobs'.
As an arranger, he collaborated with, among others, Dick Van der Harst (with whom he performed on stage at the Gentse Feesten in 2007) as well as Christine Termonia, a soprano for whom he played and arranged ancient sephardic, arabic and jewish songs with their Trio Escuro.
Bradt's music has been performed in The Netherlands, France, Spain (Denia Festival 2006), Switzerland, Lithuania (Jauna Muzika Festival) and Poland.
His works emerged on the Logos Public Domain labels LPD 012, More Automats, LPD 013, Machine Orchestra, LPD 017, StudAxe, LPD 019, Lonely Robots, as well as on the self-produced albums Bradtpack 2006 (2006) and .KoMmiX (2009). As an orchestrator/arranger, his work can be heard on LPD 018, M&M Ancient Music, on which he collaborated with his colleague Xavier Verhelst and musicians Marcel Ketels (recorder), Dirk Moelants (fiddle and viol), Stefaan Smagghe (violin) and Ludwig Van Gijsegem (tenor).
In the year 2010, he accepted three commissions: one came from the V!P Duo (Ann Vancoillie & Rudy Van der Veken), Festival En Avant Mars asked him to compose a song on 'noise' (Phantom Noise for tenor and piano, graphics and artwork by Peter Van Lancker) and from Festival Van Vlaanderen came the request to collaborate with actress Pascale Platel and bass singer Charles Dekeyser, in the theatre production C'est Moi Le Monstre.
He also wrote his first educational piece entitled The Rosarios. This short, instrumental triptych for flute, piano and viol was commissioned by Hans Roels for his research project into hyperpolyphony.

Received a commission from De Vooruit/City of Gent to compose a work for the ocarina ensemble Gruppo Ocarinistica Budriese led by Emiliano Bernagozzi, in the context of Ghent, UNESCO Creative City of Music. 't Ièn Vroagtieken ès 't Ander Nie was successfully performed at the Teatro San Leonardo, Bologna and at OdeGand in the Vooruit in Ghent.

Sebastian Bradt worked at Logos Foundation, Ghent, up to august 2014.