MASS was commissioned by former First Lady Jacqueline Kennedy for the September 1971 opening of the Kennedy Center in Washington, D.C. Titus created the role of Archie Kramer in Lee Hoiby's Summer and Smoke (after Tennessee Williams) in St. Paul in 1971, and repeated the role in his New York City Opera debut that same year.
In 1974, the baritone appeared in the world premiere of Hans Werner Henze's Rachel, la cubana, for WNET Opera Theatre, opposite Lee Venora and Marsee, conducted by the composer.
He has since been heard at Glyndebourne, Munich, Milan, Madrid, Barcelona, Vienna, Paris, Rome, London (Covent Garden), Berlin, etc.
At the Teatro alla Scala, the baritone appeared in Arabella (1992), Elektra (directed by Luca Ronconi, 1994), La fanciulla del West (1995), Die Frau ohne Schatten (in Jean-Pierre Ponnelle's production, 1999), and Salome (2002).
In his discography are recordings of Beethoven's Fidelio (as Don Pizarro) and Ninth Symphony (conducted by Giuseppe Sinopoli), Bizet's Carmen, Catalani's La Wally (as Gellner), Donizetti's Don Pasquale (with Sills, conducted by Sarah Caldwell), Haydn's La fedeltà premiata (conducted by Antal Doráti), Lehár's Die lustige Witwe (excerpts, in English, under Julius Rudel), Leoncavallo's La bohème, Mozart's Don Giovanni (led by Rafael Kubelík) and Le nozze di Figaro (as Figaro, conducted by Sir Colin Davis), Puccini's La bohème (led by Kent Nagano), and Verdi's Falstaff (as Ford, with Sir Colin Davis).