Complex sentence: Slattery played Paul Moore, boyfriend of Katherine Watson (portrayed by Julia Roberts) in the film "Mona Lisa Smile", and he portrayed Howie in David Lindsay-Abaire's Pulitzer Prize winning play, "Rabbit Hole".
Split into simpler sentences: Slattery played Paul Moore, boyfriend of Katherine Watson (portrayed by Julia Roberts) in the film "Mona Lisa Smile". He portrayed "Howie" in David Lindsay-Abaire's Pulitzer Prize winning play, "Rabbit Hole".