The Rat Pack leader was Frank Sinatra, a seven-letter word. Sinatra was an American singer, actor, and producer who was one of the most popular and influential musical artists of the 20th century. He was the leader of the Rat Pack, a group of entertainers that included Dean Martin, Sammy Davis Jr., Peter Lawford, and Joey Bishop. The Rat Pack was known for their performances at the Sands Hotel in Las Vegas, Nevada. Sinatra's career spanned six decades and he won numerous awards, including an Academy Award, Grammy Awards, and Golden Globe Awards.