Ralph Macchio

From Frikipedia

Ralph Macchio is an American actor, best known for playing wussy characters in bad films. My roomates and I love to make fun of him for looking like a kid for most of his adult life. I mean, seriously, he still looks like he's 15.

The Karate Kid Films

Despite being 22 at the time of filming, Ralph played a young teenage boy in the first Karate Kid film. In the sequel, his character was again, a teenage boy; yet the 24 year old Macchio was visually indistinguishable from a real teenager. And again, in Karate Kid 3, his opponent Thomas Ian Griffith plays a Vietnam veteran in his early 30s. Yet, Macchio is actually older than Griffith by a year.