William Coyne

William Coyne (July 14, 1861 – November 1, 1933) 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.

Early life William Coyne was born in Calumet Township, Lake County, Indiana (now part of Gary) on July 14, 1861. He was educated locally and completed a course in railway engineering through the International Correspondence Schools of Scranton. He retired from his business interests in 1930. He was elected a delegate to the 1920 Democratic National Convention, but business considerations prevented him from attending. Other delegates from Delaware attempted to obtain the vice presidential nomination for Willard Saulsbury Jr. and made use of Coyne's proxy vote, but were unsuccessful. Coyne received one vote for president on one ballot during the protracted nomination struggle at the 1924 Democratic National Convention.

In 1930, Coyne was a major contributor to the campaign fund of former Senator Thomas F. Bayard Jr., who was running for the Democratic nomination in hopes of returning to the Senate after losing his seat in 1928. Bayard's campaign was the subject of Congressional and media scrutiny because the cost of Bayard's campaign was by far the highest of any Senate race that year. He was buried at Cathedral Cemetery in Wilmington.

Family Coyne was the husband of Sarah D. Coyne (1867–1922). They were the parents of two sons, W. Carroll Coyne and Philip Coyne.