William Painter (November 20, 1838 – July 15, 1906) was an American mechanical engineer, inventor and the founder of Crown Cork & Seal Company in Baltimore (since evolved to Crown Holdings, Inc., a Fortune 500 company). He most notably invented the crown cork bottle cap, also known as the metal bottle cap.
Painter was born in 1838 in Triadelphia, then a mill town in Montgomery County, Maryland to Quakers Dr. Edward Painter and Louisa Gilpin Painter. He moved to Baltimore, Maryland in 1865 to begin a career as a foreman at the Murrill & Keizer's machine shop. He worked with manufacturers to develop a universal neck for all glass bottles and started the Crown Cork & Seal Company of Baltimore in 1892 to manufacture caps that could be used to seal the universal necks. He died in July 1906 at 67.
Painter patented 85 inventions, including the common bottle cap, the bottle opener, a machine for crowning bottles, a paper-folding machine, a safety ejection seat for passenger trains, and also a machine for detecting counterfeit currency.
He was inducted to the National Inventors Hall of Fame in 2006.