Robert McElhenney III is an American actor, producer, and, writer. He is best known for his role as Ronald "Mac" McDonald on the FX/FXX comedy series It's Always Sunny in Philadelphia (2005–present), which he created and co-developed and on which he serves as an executive producer, co-writer, and occasional director. He is also known for his role as Ian Grimm on the Apple TV+ comedy series Mythic Quest (2020–present), which he co-created and on which he serves as a co-writer and executive producer. McElhenney is the co-owner of the Welsh association football club Wrexham A.F.C. alongside Ryan Reynolds.