He studied under Aksel Schiøtz at the Colorado School of Music, and Hans Heinz at The Juilliard School. His official debut was as Marcello in La bohème in Washington, D.C., in 1969. He came to prominence, however, in Leonard Bernstein's theatre piece MASS, creating the role of the Celebrant. MASS was commissioned by former-First Lady Jacqueline Kennedy for the September 1971 opening of the Kennedy Center in Washington, D.C.
He 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. He found a home at the New York City Opera, where he was a leading baritone for many seasons. He participated in nationally-televised performances of Il barbiere di Siviglia (with Beverly Sills, 1976), Il turco in Italia (1978), La Cenerentola (opposite Susanne Marsee and Rockwell Blake, 1980), and Madama Butterfly (conducted by Christopher Keene, 1982). He made his only appearances with the Metropolitan Opera in 1976, as Harlekin in Ariadne auf Naxos, with Montserrat Caballé.
In 1973, Titus made his European debut, in Amsterdam, as Pelléas in Debussy's Pelléas et Mélisande. He has since been heard at Glyndebourne, Munich, Milan (Teatro alla Scala, Orest in Elektra, directed by Luca Ronconi, 1994), Madrid, Barcelona, Vienna, Paris, Rome, London (Covent Garden), Berlin, etc.
He made his Bayreuth Festival debut in 1998, in the title role in Der fliegende Holländer, and repeated the role in 1999. At Bayreuth in 2000, he portrayed Wotan in Das Rheingold and Die Walküre and The Wanderer in Siegfried; and repeated all three roles in 2001, 2002, 2003 and 2004. He portrayed Wotan at the Teatro Real de Madrid in 2003. He returned to Bayreuth in 2009 to portray Hans Sachs/Schuster in Die Meistersinger von Nürnberg.
In 1994, the singing-actor was awarded the title of Kammersänger, in Munich.
In his discography are recordings of Beethoven's Fidelio (as Don Pizarro), 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).
Titus retired in 2010, following a forty-year career. He lives in Germany.
- Kyle MacMillan, "East High baritone Alan Titus played MASS Celebrant," The Denver Post, April 22, 2011.
- The Metropolitan Opera Encyclopedia, edited by David Hamilton, Simon and Schuster, 1987. ISBN 0-671-61732-X