Born 1951 in Baden-Baden. In 1970 he began studying music theory, piano and conducting in Freiburg/Breisgau. A study of composition with Wolfgang Fortner and musicology with Elmar Budde followed, as well as a period of parapsychology with Hans Bender. In 1973 he moved to Cologne to study with Karlheinz Stockhausen. In 1977 he completed his conducting studies with Francis Travis in Freiburg. In 1978 and 1979 Platz received a scholarship from the Heinrich Strobel Foundation of the Südwestfunk and then lived in the USA and Paris for a longer period of time. In 1980 he attended a computer course for composers at IRCAM in Paris.  
 
From 1980 to 2001, Platz led the Ensemble Köln in Cologne.  Composers such as Bussotti, Hosokawa, Klaus Huber, Kagel, Scelsi, Xenakis wrote for the ensemble, which specialised in contemporary music. Platz appeared as guest conductor with ensembles and orchestras such as the Ensemble Modern, the Klangforum and Reihe Wien, Musikfabrik, the DSO Berlin, the WDR Radio Symphony Orchestra, the two SWR Symphony Orchestras of Freiburg/Baden-Baden and Stuttgart, the Radio Philharmonic Orchestra of the NDR Hanover, N niederrheinische Symphoniker, the Orchestre Philharmonique du Luxembourg, the Bamberg Symphony Orchestra and the Bavarian State Opera. 
 
In 1989/90 Platz lived in the Künstlerhof Schreyahn, where the multi-part work SCHREYAHN for solo violoncello, flute, trumpet, soprano, two pianos and winds was written. In 1990 he spent several weeks at Villa Serbelloni as Composer in Residence at the invitation of the Rockefeller Foundation. Two years later followed a long and formative stay in Japan. 
Platz's compositions since 1989 form parts of a diary-like work that continues in associative leaps, distributed in space, polyphonically penetrating and vaulting over each other ("Formpolyphony").
 
Lecturing and teaching activities in many European countries as well as the USA, Mexico, Israel, Indonesia, South Korea and Japan; 1986-1996 and again in 2002 lecturer at the Darmstadt Summer Course.
From 1990 Platz taught a composition class at the Maastricht Academy of Music, combined with a seminar on the performance practice of new music.
Since October 2013 Platz holds a professorship for composition and ensemble conducting of New Music at the University of Music Würzburg.

From 2000 to 2007 Platz was artistic director of the Schreyahner Herbst festival.

The text volumes TOP: Skizzentagebuch and … weil die Welt und wir mit ihr so sind (Texts about Music 1972–2014) were published by Pfau-Verlag.
In 2013 Bärenreiter-Verlag published Techniques of Violin Playing (with Irvine Arditti). 
For 2021 a volume on Robert HP Platz is in preparation (Pfau-Verlag, ed.: Gordon Kampe).

Since 2016 the piano manufacturer Steingraeber has been building the first midi grand piano with fixed transducers according to his specifications.

Since 2005 the composer has been a member of the Bureau du Directeur of the Electronic Studio Henri Pousseur, Liège.

Numerous CDs document the compositional and conducting work of Robert HP Platz. His portrait CD Mauro Lanza with the Ensemble Alternance was awarded by the Académie Charles Cros, his first Hosokawa CD with NEOS received the Clef d'Or as "Best CD of 2009“.