William Atchison O'Neill (August 11, 1930 – November 24, 2007) was an American politician and member of the Democratic Party who served as the 84th Governor of Connecticut from 1980 to 1991.

[4] Upon his return, he ran the family business—an East Hampton tavern where residents and politicians often met and where he, by his own admission, learned to listen.

When Grasso resigned for health reasons in December, 1980 (she would pass away the following February), O'Neill became Governor and was elected to a full term in 1982 and re-elected in 1986.

Facing plummeting approval ratings and a budget situation continuing to deteriorate despite the 1989 tax hike,[6] O'Neill decided in early 1990 to bow out of a re-election bid.

"I always thought the secret to his success was that he was genuine," said John Droney, who was chairman of the state Democratic party during O'Neill's last term.