O'Donnell (born November 17, 1960) is a Democratic member of the New York State Assembly, representing the 69th district in Manhattan, made up of the neighborhoods of Manhattan Valley, Morningside Heights, and portions of the Upper West Side and West Harlem.
He is older brother to Rosie O'Donnell.
In 2008 he was considered by New York Governor David Paterson to fill the Senate vacancy created by the appointment of Hillary Clinton as President Obama's Secretary of State.
Paterson ultimately appointed upstate Congresswoman Kirsten Gillibrand to the seat.O'Donnell was the legislative sponsor of the Marriage Equality Act during its successful passage and signature into law on June 24, 2011.