Step 1 : Introduction to the question "Which "Rat Pack" celebrity was the brother-in-law of President John F. Kennedy?"
Peter Lawford enjoyed a successful career as an actor and entertainer, married into one of the most high-profile families in American history, and was a member of the famed Rat Pack. His first marriage, in 1954, was to socialite Pat Kennedy, the younger sister of President John F. Kennedy. Peter Lawford was also well known for performing in Las Vegas with Frank Sinatra and Sammy Davis, Jr. as part of the "Rat Pack." He was the first actor to kiss Elizabeth Taylor on camera, and the last to speak to Marilyn Monroe before she died.