John Krasinski is an actor on The Office.
John Burke Krasinski ( [ krəˈzɪnski ] born October 20 , 1979 ) is an American actor and filmmaker . He is widely known for his portrayal as Jim Halpert on the NBC comedy series The Office , for which he received critical acclaim and won numerous awards . The Office (U.S. TV series) . The Office initially featured Steve Carell , Rainn Wilson , John Krasinski , Jenna Fischer and B. J. Novak as the main cast ; the show experienced numerous changes to its ensemble cast during its run .