He graduated from the Sofia Musical Academy ‘Pancho Vladigerov’ and studied there with Konstantin Karapetrov and Nedialko Nedialkov.
Later completed the Academy for Young Singers at Teatro alla Scala studing with Leyla Gencer, Luigi Alva, Teresa Berganza and Luciana Serra. There he sang in a production of Verdi's early opera Oberto Conte di San Bonifacio. The next year he performerd in Teatro Arcimboldi and Teatro Bergamo the opera of Donizzetti Ugo Conte di Parigi that were recorded with Dynamic. He took part in the Belvedere Competition in Vienna and won both the Verdi Prize and the special Chamber Opera Prize. As a result of these victories, he performed the role of Don Basilio in Il Barbiere di Siviglia in Vienna. Later in this role, he performed at the Teatro alla Scala, as well as in Limoges, Cannes, Reims and Dijon.
In the singer's repertoire are also the leading and main parts in the operas Verdi's Aida, Attila, Un ballo in maschera, Puccini’s Tosca, Turandot, Bizet's Carmen, Berlioz's Les Troyens, Donizetti's Lucia di Lammermoor, L'elisir d'amore, Mozart's Don Giovanni, which he performs in the biggest theatres in Italy, Germany, France, Bulgaria, the USA, Canada and Japan. In 2015 Deyan was again Don Basilio and Raimondo making a big tournee in France. He performed the role of Monterone in Bogota (Columbia). In 2016 he sang Timur from Turandot in Bari (Italy). In 2017 Raimondo from Lucia di Lammermor in Las Palmas (Spain). Laureate of the Concorso Iris Idami Corradetti in Padua (2002, 1st Prize, ‘Arrigo Boito’ Prize).