He studied at the Rome Conservatory, furthering his studies in composition with a PhD with Aldo Clementi, and in conducting with Franco Ferrara.
In 1975 he co-founded “Spettro sonoro”, an ensemble dedicated to contemporary music.  in 1979, they were was first to perform the complete musical compositions of Friedrich Nietzsche.
As a pianist, he has collaborated with the Rai Symphony Orchestra in Rome, and with the Orchestra of the Teatro dell’Opera in Rome, and taught in several Italian Conservatories for more than twenty years.
From 1985 Dal'Ongaro started a 30-year collaboration with Rai Radio, becoming Rai 3’s Controller of programming between 2000 and 2015, and from 2008 becoming the Director General of Rai National Symphony Orchestra. From 2011 to 2016, he created and established the TV programme Petrushka for Rai5 TV.
He has written several essays on music, among them: La musica tra suono e silenzio in “Atlante del Novecento” (UTET, 3 volumes, 2000), and La musica liquida del XXI Secolo (NOVA, L'Enciclopedia UTET,  2005). In 1986 he published an essay dedicated to the analysis of Giacomo Puccini’s works (Pacini Editore, Pisa).
His own compositions, published by Suvini-Zerboni and recorded on several albums, have been performed by the most important Italian and international ensembles (including the Arditti Quartet, Ensemble Recherche, Ensemble 2E2M, Ex-Novo Ensemble). He has collaborated, among others, with several distinguished artists such as Luca Ronconi, Carlo Cecchi, Claudio e Daniele Abbado, Luciano Berio, Michele Serra, Stefano Benni, Alessandro Baricco.
Between 1993 and 1999, he was a music consultant for Romaeuropa Festival, and became President of “Nuova Consonanza” from 1996 to 1999. Other appointments have included Music Programmer for the Venice Biennale Contemporary Music Festival (February 1999-March 2001), continuing as a consultant between 2003 and 2004. He was Vice-President of the “Centro Tempo Reale”, founded by Luciano Berio. He is currently a member of the Advisory Board of the Accademia Filarmonica Romana, and of the scientific committee of the “Claudio Abbado” Foundation and of the “Luciano Berio” Study Center.
For his work as a producer, he was awarded the “Prix Italia” and also the “Ugo Gregoretti” Prize in 2008. In 2012 the Italian President Giorgio Napolitano awarded him with the title of “Knight of the Order of Merit of the Italian Republic”.
In 2008,  he became a member of the Accademia Nazionale di Santa Cecilia in Rome, and from the 20th of February 2015 he has been elected as President-Superintendent of this institution.

In 2017, he was named a member of the Steering Committee of the Services Centre for Recreational, Cultural, Artistic, and Performance activities at Rome’s Università La Sapienza.