He was born at Naarden in the Netherlands. He trained from 1962-1966 at the School of Graphic Arts (in Amsterdam, then the Rijksacademie voor beeldende kunsten (National Academy of Visual Arts) (1968).
Schmüll's early commercial work has included the engraving of postage stamps and heraldic emblems. In 1973 he established his own art workshop and has since worked as an independent artist, latterly in collaboration with Karl Boegli, Master Engraver.
Bertil is widely exhibited in Europe.