Sloane was married seven times. His last marriage, to wife Mimi, lasted from age 54 until his 1985 death in New York at age 80. He died from a heart attack while walking down the street to a luncheon held in his honor. A young woman who was a passer-by saw Sloane go into cardiac arrest as he held onto a parking meter before collapsing to the sidewalk; she telephoned for help from a nearby phone booth. The luncheon celebration being held in his honor marked the publication of his memoir published at age eighty, "Eighty: An American Souvenir".