Bostridge studied at Westminster School and the Universities of Oxford and Cambridge, where he read history and philosophy. He received his doctorate from Oxford, on the significance of witchcraft in English public life from 1650 to 1750, in 1990, and was a post-doctoral fellow at Corpus Christi College, Oxford, before embarking on a career as a singer, having won the 1991 National Federation of Music Societies Award and support from the Young Concert Artists' Trust.

Bostridge made his Wigmore Hall debut in 1993; his Purcell Room debut (an acclaimed Winterreise) and his Aldeburgh Festival debut in 1994; in 1995 he gave his first solo recital in the Wigmore Hall (winning the Royal Philharmonic Society's Debut Award); in 1996 he gave recitals in Lyon, Cologne, London and at the Aldeburgh, Cheltenham and Edinburgh Festivals, and in 1997 at the Alte Oper, Frankfurt.

On the concert platform he has appeared with the London Symphony Orchestra under Sir Colin Davis and Rostropovich, the Scottish Chamber Orchestra under Sir Charles Mackerras, and the City of Birmingham Symphony under Sir Simon Rattle.

His first recording for Hyperion Records was a Britten song recital, The Red Cockatoo with Graham Johnson, and his subsequent recording of Die schöne Müllerin in Hyperion's Schubert Edition won The Gramophone´s Solo Vocal Award for 1996.

Bostridge made his operatic debut in 1994, aged 29, as Lysander in A Midsummer Night's Dream with the Australian Opera at the Edinburgh Festival. In 1996 made his acclaimed debut with the English National Opera, singing his first Tamino (The Magic Flute). In 1997 he sang Quint in Deborah Warner's new production of The Turn of the Screw under Sir Colin Davis for the Royal Opera. He has recorded Flute (Britten's A Midsummer Night's Dream) with Sir Colin Davis for Philips Classics; Belmonte (Die Entführung aus dem Serail) with William Christie for Erato, and Tom Rakewell (The Rake's Progress) under John Eliot Gardiner for Deutsche Grammophon.

In 1997 he made a film of Winterreise for Channel 4 directed by David Alden, and his book Witchcraft and its Transformations: 1650 – 1750 was published by Oxford University Press. He has written on music for The Times Literary Supplement, Opernwelt, BBC Music Magazine, Opera Now and The Independent. In 1999 Methuen published his second book, on music and singing.

Later engagements included recitals in Paris, Stockholm, Lisbon, Brussels, Amsterdam and the Vienna Konzerthaus. In North America he appeared in recitals in New York City at the Frick Collection in 1998 and Alice Tully Hall in 1999 and made his Carnegie Hall debut under Sir Neville Marriner. Also in 1998 he sang Vasek in a new production of The Bartered Bride under Bernard Haitink for the Royal Opera and made his debut at the Munich Festival as Nerone (L'incoronazione di Poppea) and in recital (Winterreise at the Cuvillés Theatre). In 1999 he made his debut with the Vienna Philharmonic Orchestra under Sir Roger Norrington.

In 2004, Ian Bostridge was made CBE for his services to music. His brother is the biographer and critic Mark Bostridge[1], who is writing a book about his relationship with his singing sibling, called My Brother, Myself.