Giles Farnaby was born about 1563, perhaps in Truro, Cornwall or near London. His father, Thomas, was a Cittizen and Joyner of London, and Giles may have been related to Thomas Farnaby (c. 1575–1647), the famous schoolmaster of Kent, whose father was a carpenter. But it was his cousin Nicholas Farnaby (c. 1560–1630), who may have turned him to music. Nicholas was a virginal maker, at this time a generic word that included the entire family of plucked keyboard instruments: the harpsichord, virginal, muselar and doubtless the clavichord, and it is for these instruments that Farnaby’s compositions are best known. Like his father however, Giles trained as a joiner or cabinet-maker, starting his apprenticeship in about 1583, and gave this trade as his occupation for most of his life.

He married Katherine Roane on 28 May 1587, and first lived in the parish of St. Helen’s Bishopsgate, in London. The couple had a daughter, Philadelphia, baptised on 8 August 1591, when the Farnabys moved to the neighbouring parish of St Peter’s, Westcheap, and later a son, Richard Farnaby (1594–1623). After Philadelphia’s premature death, prior to 1602, the Farnabys had three more children: a son Joy (1599), a daughter, also baptised Philadelphia (1602), and a last son, Edward (1604).

In spite of his social background, hardly suited at this time to a university education, he graduated from Christ Church, Oxford on 7 July 1592, receiving a Bachelor’s degree in music.  This was the very same day that John Bull obtained his degree: Bull evidently knew Farnaby, and influenced his musical style.

In 1602 the family moved to Aisthorpe in Lincolnshire, where they remained until at least 1610. Farnaby obtained a position in the household of Sir Nicholas Saunderson of Fillingham, as music teacher to his children. By 1614 the Farnabys had returned to London, registered at Grub Street, Cripplegate in 1634, where Giles died in 1640 and was buried on 25 November.

Farnaby is considered one of the great English virginalists, together with William Byrd, John Bull, Orlando Gibbons, Peter Philips and Thomas Tomkins among others. Unlike them however, he is the only one not to have been a professional musician.

The Fitzwilliam Virginal Book, contains 52 of his pieces. Notable among them are 11 fantasias, a wonderful and technically demanding set of variations called Woody-Cock, and short but charming descriptive pieces such as Giles Farnabys Dreame, His Rest, Farnabyes Conceit and His Humour. There are also four pieces by his son, Richard.

In addition to his keyboard compositions, Farnaby also composed madrigals, canzonets and psalms.