Everyone knows of his many marriages. I remember Merv Griffin ridiculing him for it on his talk show in the 70s.
My father worked at the Salt Lake City airport. Celebrities had layovers, waiting for connecting flights. (Only the rich flew then.) My father was sent to tell Mickey and his mother that their flight had arrived and drive them back. He found them out in a snow field. The kid was rolling around by himself laughing and playing, just like the parts he was playing.
One time Katherine Hepburn arrived without makeup and looked homely. She ran into a rest room and hid from reporters a couple of hours till her plane arrived.