From Wikipedia, the free encyclopedia. Michael John McKean (born October 17, 1947) is an American actor, comedian, writer, composer and musician, perhaps best known for his portrayal of Squiggy's friend, Leonard 'Lenny' Kosnowski, on the sitcom Laverne and Shirley; and for his work in the Christopher Guest ensemble films, particularly as David St. Hubbins of Spinal Tap.