The most prolific composer of the London stage of the late-eighteenth century, Samuel Arnold was also a popular composer for London's pleasure gardens. He wrote songs ('gratis') for Vauxhall during the 1760s when he was establishing his reputation and all-sung burlettas for Marylebone during the time he was owner-proprieter (1769-1774). Arnold's Six Overtures, Op.8 were undoubtedly composed for Marylebone: they were published in parts by John Welcker in ca 1771 (lost) and reissued by Longman & Broderip a decade later; a keyboard version (with minor variants) testifies to their popularity as home entertainment.

Samuel Arnold was born in London, the son of Thomas Arnold and probably Princess Amelia, Handel's pupil. He studied under Bernard Gates, a student of John Blow, at the Chapel Royal and from the mid 1760s he was an active composer for the summer gardens concerts. Arnold began his theatrical activities in 1764 and within a decade established his reputation, particularly with The Maid of the Mill (1765), the first modern English opera with action-finales, and The Prodigal Son, an oratorio performed at the Oxford University Encaenia in 1773.

At the age of 29, Arnold, in partnership with the violinist Thomas Pinto, took up the proprietorship of Marylebone Gardens but despite good-quality music performed there, the owners faced a constant struggle against financial adversity and strenuous efforts were necessary to attract the public. Burlettas (Italian comic operas in translation) were a particular speciality, being staged in a separate small theatre, and so were Torre's fireworks displays. Francois Hippolyte Barthelemon, one of London's foremost virtuosi (admired by Fanny Burney's Evelina) was leader of a small but accomplished orchestra. Arnold retired from Marylebone in financial ruin when he lost around £10,000 as a result of embezzlement.

Arnold resumed his professional association with the patent theatres when, in 1777, he was engaged by George Colman, the elder as composer and music director of the Little Theatre in the Haymarket. He composed over 60 stage works over the next twenty years, some with impressive overtures, such as those for The Castle of Andalusia (1782) and Turk and No Turk (1785), as well as incidental music, overtures and and insertion arias for other composer's works.

From the mid 1780s Arnold was in a position to combine his summer directorship of the Little Theatre with several other posts in London, such as organist and composer to the Chapel Royal (from 1783) and organist to Westminster Abbey (from 1793). In 1789 he became conductor of the Academy of Ancient Music and in 1790 founded the Graduates Meeting, a society of academic musicians which included Haydn among its associates. From 1786 Arnold was dedicated to editing a complete Handel edition, 180 parts of which were completed. Arnold was buried in Westminster Abbey.