Robert Banfield Capron Jr. (born July 9, 1998) is an American actor. He is best known for starring as Rowley Jefferson, Greg Heffley's best friend, in the first three installments of the Diary of a Wimpy Kid film series. More recently, Capron is known for starring as Mason in the drama series Elementary, and as David Lewan in the film The Polka King. (Via Wikipedia)