Jeff Stewart trained as a singer at the Guildhall School of Music & Drama, winning the Harold Rosenthal award for outstanding achievement, and then at the National Opera Studio.

He has appeared in concert and recital all over the world, singing most of the great oratorio works.  Highlights have included Bach St. Matthew Passion in Tampere under the baton of Andrew Manze as well as in Coventry Cathedral, Carmina Burana in the concert hall of the Firbidden City in Beijing, Haydn's Nelson Mass with Mozart's Dominicus Messe in Escondido, Florida, to celebrate 200 years of the Mission St. Louis Rey, and Weil's The Seven Deadly Sins with Susan Graham, under the baton of Sir John Elliot Gardiner having previously performed it with Marianne Faithfull under Carl Davis.  He has recently given acclaimed performances of Schumann's Dichterliebe. 

He has appeared in Opera Houses throughout Europe, including the Royal Opera House Covent Garden, English National Opera, Opera North, Deutsche Oper am Rhein Düßeldorf, Komische Oper Berlin, Schwerin, Bremen & Skopje, in a wide variety of repertoire that includes  Edgardo (Lucia di Lammermoor), Nemorino (L'Elisir D'Amore), Ernesto (Don Pasquale), Steva (Jenufa),Rodolfo (La Boheme), The Duke of Mantua (Rigoletto), Male Chorus (Rape of Lucretia), Pinkerton (Madame Butterfly), Tamino (Magic Flute), Ferrando (Cosi fan tutte), Walther (Tannhäuser), Andres (Wozzek), Alfred (Die Fledermaus), Gounod's Romeo and Gustavus (Un Ballo in Maschera). 

Jeff is a professor of the vocal faculty at the Royal College of Music.

In 2004 he became the choirmaster of Holy Trinity Church Bledlow, which is now a thriving ensemble which regularly sings in England's great cathedrals. In 2009 he became the Musical Director of Uxbridge Choral Scociety with whom he has so far performed the Rossini Petite Messe Solenelle, Haydn's Missa Sancti Nocolai and Te Deum in C, and Schubert's Mass in G.