L.C. Wyon was born in the Royal Mint, London in 1826. His father, William Wyon, was an engraver at the Mint and became Chief Engraver in 1828. While studying at the Merchant Taylor's School in London Leonard was tutored in die engraving by his father and was appointed Second Engraver at the mint in 1843. The position of Chief Engraver ceased with the death of William in 1851. Leonard took over its duties as Resident Engraver and later Modeller and Engraver.
The first sovereign and half-sovereign designs of the Sydney Mint in 1855 were derived from the work of his father, but in 1857 new obverse portraits of Queen Victoria by Leonard Charles Wyon were adopted. These remained in use until 1870 after which the Sydney coins were the same as those of London.
In 1860 he was charged with designing the new bronze coins for the United Kingdom and in 1887 he engraved the Jubilee head of Queen Victoria for the silver and gold coinages. He prepared the dies for most British military and naval medals from 1851 to 1891.
Leonard Charles Wyon died at his home in London, on 20 August 1891 and is buried at Paddington Old Cemetery.