Orphaned at age 15, he worked as a tutor at the Grand Theatre of Verviers while pursuing his studies, including from Francis Duyzings for harmony.

Noticed by the French composer and teacher Vincent d'Indy in 1897, Dupuis was invited to work with him at the Schola Cantorum in Paris.

In 1903 he won the Prix de Rome Belgium (not to be confused with the French Prix de Rome) with his cantata La Chanson d'Halewyn and on 5 March his opera Jean-Michel premiered at La Monnaie, the Royal Theatre of the Mint in Brussels..

After the death of Albert Dupuis, a collection was created by his descendants, who later donated it to the King Baudouin Foundation in order to ensure its preservation.

The Albert Dupuis collection consists mainly of printed and manuscript scores of the composer's works, manuscript librettos, press clippings, concert programs, photographs, and correspondence covering his entire career (letters from Eugène Ysaÿe, Vincent d'Indy, Edgar Tinel and Octave Maus), notes by Dupuis taken during d'Indy's course at the Schola Cantorum in 1897, as well as a few objects, including the composer's conducting stick.