John Stanley was born in London on 17 January 1712. At about the age of two, he had the misfortune to fall on a marble hearth with a china basin in his hand, an accident which left him almost blind.
He began studying music at the age of seven. Under the guidance of Maurice Greene, composer and organist at St. Paul's Cathedral, he studied "with great diligence, and a success that was astonishing" (Burney). At the age of nine he played the organ, probably as an occasional deputy, at All Hallows Bread Street. The organist died on 23 September 1723 and exactly one month later eleven-year-old Stanley was appointed organist to the church at a salary of £20 per annum.
When he was fourteen "in preference to a great number of candidates" (Burney) he was chosen as organist at St Andrew's, Holborn, and at the age of seventeen became the youngest person ever to obtain the Bachelor of Music degree (B.Mus.) at Oxford University.
In 1734 he was appointed organist to the Society of the Inner Temple - a position which he held until his death in 1786. It was at the ancient Temple Church that his brilliant playing upon the organ and harpsichord attracted the attention of many fine musicians including George Frideric Handel, who regularly visited the church to hear him. Stanley was also an outstanding violinist.