A professional violinist and amateur violin maker, John Day was born into a family of musicians in London, England in 1830. As a young boy, he performed with his older sister, Ellen Day, a piano prodigy who performed for Queen Victoria, Franz Liszt, Felix Mendelssohn, and Fréderic Chopin. After concertizing in Brussels, Belgium in 1843, Day was accepted as a student by Charles de Beriot, later appearing as a soloist with the London Philharmonic and other English orchestras, and on numerous concert series, including the famous provincial festivals of Louis-Antoine Jullien. In 1847, Day took a position in Queen Victoria's Private Band—a post he would hold for over 50 years, performing for ceremonial occasions and concerts hosted by Prince Albert at Buckingham Palace. Also an accomplished organist, Day was employed by local churches. In the 1860s, Day began building violins as a hobby, copying models of Amati and his own Guarneri del Gesù, which were highly praised for their beauty and tone quality. He promoted his instruments and shared his opinions on violin making in The Strad magazine, and in 1897, four of Day's instruments were chosen for display in the Victoria Loan Exhibition at the Crystal Palace: two del Gesù model violins (1852 and 1870), an Amati violin (1887), and a del Gesù viola (1885). He died in London in 1905.