William Coyne was an American corporate executive and political figure. He was most notable for his work as a vice president and director of E. I. du Pont de Nemours and Company and a prominent supporter of the Democratic Party.

The 1924 Democratic National Convention, held at the Madison Square Garden in New York City from June 24 to July 9, 1924, was the longest continuously running convention in United States political history. It took a record 103 ballots to nominate a presidential candidate. It was the first major party national convention that saw the name of a woman, Lena Springs, placed in nomination for vice president. John W. Davis, a dark horse, eventually won the presidential nomination on the 103rd ballot, a compromise candidate following a protracted convention fight between distant front-runners William Gibbs McAdoo and Al Smith.