Suzanne Danco was born in Brussels and grew up in a Flemish background although French was her native language. She studied at the Conservatoire Royal de Bruxelles, and in 1936 she won a vocal competition in Vienna, after which the conductor Erich Kleiber recommended that she continue her studies in Prague with Fernando Carpi. She appears to have made her concert debut in Italy in 1940, and her stage debut in 1941 at the Genoa Opera, playing Fiordiligi in Mozart's Così fan tutte.
She appeared in most of the major opera houses in Europe through the 1940s and 1950s, including at La Scala (Jocasta in Oedipus Rex by Stravinsky, and Ellen Orford in Peter Grimes), at the Teatro di San Carlo (Marie in Wozzeck), at the Royal Opera House Covent Garden (Mimi in La bohème), and at the festivals of Glyndebourne and Aix-en-Provence (Fiordiligi and Donna Elvira). In 1951, Danco performed in Boston at a special Peabody Mason Concert series