He was born Jean-Joseph Merlin in 1735 in the city of Huy, Belgium. He was an inventor, noted for the invention of inline skates in 1760. He also improved musical instruments and manufactured automata, such as Cox's timepiece. He created Merlin's Mechanical Museum to display his machines.
In conjunction with London inventor James Cox, Merlin was also responsible for the Silver Swan automaton now on display at the Bowes Museum in County Durham, England. He worked in Paris and later in London, where he died in 1803.
A remarkable working timepiece created by Merlin is on display at Kenwood House, Hampstead, north London, where there is also displayed a portrait of Merlin by Thomas Gainsborough.