Who was married to the woman known as Jackie O until his assassination in 1963?
Jackie O (disambiguation) Jackie O often refers to Jacqueline Onassis. It may also refer to:
Kathleen Cavendish, Marchioness of Hartington Kathleen Agnes Cavendish, Marchioness of Hartington ("née" Kennedy; February 20, 1920 – May 13, 1948), also known as "Kick" Kennedy, was an American socialite. She was the daughter of Joseph P. Kennedy, Sr. and Rose Kennedy, sister of future U.S. President John F. Kennedy, and wife of the Marquess of Hartington, heir apparent to the 10th Duke of Devonshire.