Rob McElhenney portrayed the role of "Aldo" on Lost. Rob McElhenney is best known as the creator, writer, and executive producer of the FX TV series It's Always Sunny in Philadelphia, which he also stars in as the character Mac. McElhenney made his film debut with a bit part in The Devil's Own and followed that up with bit parts in A Civil Action and Wonder Boys. More recently, he had a slightly more substantial parts in Latter Days and The Tollbooth. He is a 1995 graduate of St. Joseph's Preparatory School.