have a role in (something)

1. To have a specific involvement or participation in something. There's no use lying to the committee, Mr. Marshall, as we know for a fact that you had a role in hiding your company's losses from its investors. Listen up, Joe. You're going to have a role in this operation, too. I had no role in this, Officer, I swear! I had no idea they were stealing money!

2. Literally, to have a job portraying a certain character in a performance. I hear that Samantha has a role in some new film. She's really making her way into the big leagues! I bombed my audition and didn't end up getting a role in the play. Plenty of people go to Hollywood and never end up getting a role in anything.