[3][4] He worked for renowned companies, such as the Burgtheater in Vienna (The Bacchae by Euripides, 1973; The Birds by Aristophanes, 1975; The Oresteia by Aeschylus, 1976), the Vienna State Opera (Il viaggio a Reims by Rossini, 1988), the Rossini Festival in Pesaro and the Salzburg Festival (Die Riesen vom Berge [I giganti della montagna] by Luigi Pirandello, 1994; Don Giovanni by Mozart, 1999).
His work was often seen at the Teatro alla Scala, from 1974: Die Walküre, Siegfried, Wozzeck (conducted by Claudio Abbado), Don Carlos, Donnerstag aus Licht, Les Troyens (with Dunja Vejzovic as Didon), Ernani (with Plácido Domingo, conducted by Riccardo Muti), Samstag aus Licht, L'Orfeo (of Luigi Rossi), Il viaggio a Reims, Aïda (with Maria Chiara), Fetonte, The Tale of Tsar Saltan, Guillaume Tell, Oberon, Lodoïska, Elektra (with Alan Titus as Orest), La damnation de Faust (with Jerry Hadley), Tosca, Ariadne auf Naxos, Moïse et pharaon, Europa riconosciuta, Il trittico, and The Makropulos Affair.
Ronconi managed the Teatro Stabile di Torino from 1989 to 1994, where he directed an imposing edition of Karl Kraus' The Last Days of Mankind, with more than sixty actors, staged in the Lingotto (1991).
Ronconi collaborated with important stage designers, among them Pier Luigi Pizzi (The Bacchae, Die Walküre, Siegfried), Luciano Damiani (The Birds, The Oresteia, Don Carlos), and Ezio Frigerio (Les Troyens).
His operatic productions also included Carmen (with Mignon Dunn and Franco Corelli, 1970), Das Rheingold (1979), Nabucco (1977), Il trovatore (1977), Norma (with Renata Scotto, 1978), Macbeth (1980), La traviata (1982), L'Orfeo (1985 and 1998), Don Giovanni (1990 and 1999), The Turn of the Screw (1995), Il ritorno d'Ulisse in patria (1998), Lohengrin (1999), L'incoronazione di Poppea (2000), and Intolleranza (2011).