Dutch harpsichordist Gustav Leonhardt was born on 30 May 1928 in 's‑Graveland near Hilversum. He studied harpsichord and organ in Switzerland at Schola Cantorum Basiliensis with Eduard Muller, and went on to study with Hans Swarowsky in Vienna, where he made his debut as a harpsichordist and first met Nikolaus Harnoncourt.
Also a church organist, Leonhardt began making recordings of the keyboard works of J S Bach in the 1950s, and he also created and led the Leonhardt Baroque Ensemble (which included counter-tenor Alfred Deller and cellist Nikolaus Harnoncourt) in recordings of Bach cantatas. Later, Leonhardt and Harnoncourt worked on a joint project, recording all of Bach's Cantatas, each conductor performing his assigned cantatas separately with his own group.
He died in Amsterdam on 16 January 2012, aged 83.