Ellegaard was the son of a cabinet maker and began studying the instrument at the age of eight.
Free-bass accordion
In 1952 Ellegaard competed at the Confédération internationale des accordéonistesCoupe Mondiale in the Netherlands. At this time he heard a free-bass accordion and decided he must get such an instrument. In the meantime, he studied literature at Schneekloth's College in Copenhagen and graduated with honors. After military service he was given an American Embassy Literary Award for study in the United States and supported himself in part by playing this accordion in restaurants and at popular concerts. Ellegaard returned to Denmark in 1958 and the Danish pianist/composer Vilfred Kjaer wrote a concerto for him, which led to the creation of a very popular concerto for accordion by the composer Ole Schmidt. Ellegaard continued, Symphonic Fantasy and Allegro was premiered by the Danish Radio Symphony with the composer conducting. Ole Schmidt made the following comment about the work, "I hated accordion until I met Mogens Ellegaard. He made me decide to write an accordion concerto for him." Some of the works Mogens Ellegaard commissioned and premiered are:
* Symphonic Fantasy and Allegro, op. 20 for accordion and orchestra
* Toccata 1 op. 24
* Toccata 2 op. 28
* Escape of the meatball over the fence
Ellegaard has performed this contemporary music in solo recitals and chamber music concerts in Moscow, New York City, Tel Aviv, Amsterdam, Rome, Paris, Dublin, Reykjavík, Zagreb and Toronto, to name a few. He has been a soloist with London's Royal Philharmonic, the Detroit Symphony, the Toronto Symphony, Sudwestfunk Symphonie Orchester, Stockholm, Oslo and Helsinki Philharmonic orchestras, BBC Scottish Symphony, and all of the Danish orchestras. He has appeared at international festivals usch as Warsaw Autumn, I.S.C.M., and Bergen. He was for many years a member of the Trio Mobile with percussionist Bent Lylloff and guitarist Ingolf Olsen, commissioning pieces from Thorbjörn Lundquist, Ib Nørholm, Arne Nordheim, Per Nørgård, Finn Mortensen and others. As a chamber musician he was later concertizing extensively with a trio consisting of his Hungarian born pianist, and accordionist wife, Marta Bene and percussionist Gert Sørensen.
Accordion professor
In the early-1960s Ellegaard began working with Lars Holm at the MalmöSweden Accordion Studio where he taught free-bass accordion. He wrote "Comprehensive Method for the Chromatic Free Bass System" which was published by Hohner in New York City in 1964. In 1970 he founded the accordion department at The Royal Danish Academy of Music in Copenhagen. In 1977 he became a full professor. In 1989 he was appointed head of the accordion faculty of the Hochschule fur Musik und Darstellende Kunst in Graz, Austria. He has conducted master class courses and seminars at Warsaw's Chopin Academy, Helsinki's Sibelius Academy, Trossingen Bundesakademie, and Conservatories in the Netherlands, Spain, etc. Today his students teach at Scandinavian music academies, as well as at the Royal Academy in London, many Conservatories in Germany, the Netherlands, and other locations.
