James Oldfield trained at Trinity College, Cambridge and at the Royal College of Music, London, and then completed an Artist Diploma in Opera at the Royal College of Music International Opera School. James' awards and scholarships included the Eric Joseph Shilling Prize for Opera, the RCM Sir Thomas Allen Scholarship, the inaugural Independent Opera/Royal College of Music Scholarship (2008), a Sybil Tutton Award administered by the Musicians Benevolent Fund, and the 2010 Leonard Ingrams Award from Garsington Opera.

James made his professional debut with Garsington Opera as Figaro in 'Le nozze di Figaro', and since then has performed with Gothenburg Opera (Nick Shadow in 'The Rake's Progress'), The Royal Opera House (Ludd in 'Ludd & Isis') and Opera North (Achilla in Handel 'Giulio Cesare'). As a seasoned concert soloist, he has performed with the Hallé, RTE Symphony Orchestra, The Philharmonia, London Symphony Orchestra, Manchester Camerata and the Northern Sinfonia. James' debut with the Huddersfield Choral Society (Handel 'Messiah') was released as a live recording by Signum Records.

James teaches singing in London and in Cambridge.