Mirella received her education at the Royal Balletschool of Antwerp and Nederlands Dans Theater (Young talent class by Ivan Kramar).
She works as an independent teacher for companies and schools and is director of the international private school 'Balletschool Mabel Alter'. Former NDT dancer Mabel Alter founded the school in 1970 and stepped down in 2002. 
The Mabel Alter School is owned by Mirella Simoncini since September 2002.

Guest Teaching
In 2012 she began as a guest teacher for Britain's national dance company Rambert (artistic director Mark Baldwin). A year later the company moved into a new building and Mirella was invited to teach the company class for the Open House Event with audiences watching class. Since than she returned many times to Rambert and has been a guest teacher at the internationally renowned British Dance Company Wayne McGregor (artistic director Wayne McGregor), De Dutch Junior Dance Division (artistic directors Thom Stuart & Rinus Sprong), and Project Sally Maastricht (artistic directors Ronald Wintjens & Stefan Ernst).

Helping Young Talent to get the most out of themselves
Mirella enjoys supporting the Dutch dance scene making available scholarships for future dancers a.o. The Royal Conservatoire of The Hague, National Ballet Academy in Amsterdam, ArtEZ Dansacademie in Arnhem and international dance competitions. 

Summerschool Den Haag
In 2003 she initiated Summerschool Den Haag, collaborating with appreciated personalities in the international ballet scene. Her approach regarding small classes and the possibility of creating an individual schedule for each student made Summerschool Den Haag one of Holland's most appreciated schools for the personal touch in dance training.