Sir Thomas Allen is an established star of the great opera houses of the world. At the Royal Opera House, Covent Garden, where in 2014 he celebrated the 40th anniversary of his debut with the company, he has sung no less than fifty roles.  In 2006, he also celebrated his twenty-fifth anniversary of his début at the Metropolitan Opera, New York. Equally renowned on the concert platform, he appears in recital in the United Kingdom, throughout Europe, in Australia and America, and has performed with the world's greatest orchestras and conductors. The greatest part of his repertoire has been extensively recorded.

Recent successes have included the title role in Gianni Schicchi at the Royal Opera House, Covent Garden, the Spoleto Festival and for the Los Angeles Opera, Faninal Der Rosenkavalier at Covent Garden and for the Metropolitan Opera, New York, and Prosdocimo Il turco in Italia at Covent Garden and in Los Angeles. His engagements this season include Don Alfonso at the Royal Opera House, Covent Garden, and with the Bayerische Staatsoper in Munich and Hong Kong; and his debut at the Bolshoi Theatre in Moscow in the role of Faninal.

He made a triumphant directing debut with Albert Herring at the Royal College of Music in 2003. He has since directed successful productions of Le nozze di Figaro for Arizona Opera, and Don Giovanni and Così fan tutte for Samling Opera at The Sage, Gateshead. A regular guest at Scottish Opera, his productions of Il barbiere di Siviglia and Le nozze di Figaro have enjoyed widespread critical acclaim.

In the New Year's Honours of 1989 he was created a Commander of the British Empire and, in the 1999 Queen's Birthday Honours, he was made a Knight Bachelor. In 2013 he was awarded the Queen's Medal for Music, and this year was given an honorary doctorate from the Royal Academy of Music. He is Chancellor of Durham University.