From Wikipedia, the free encyclopedia. John P. Navin Jr. (born July 24, 1968) is an American film and television actor from Philadelphia. He is well known for his roles in the 1981 drama film Taps and the 1983 movie Losin' It, in both of which he co-starred with Tom Cruise. He also starred in National Lampoon's Vacation as Cousin Dale. Navin starred in the short-lived 1983 television series Jenn... show more