Martin Sheen has been doing Catholic social justice work like this for decades. He is close to the Berrigan family too, and in a recent obituary thread on Phillip, I posted a brief interview with Martin on CNN, in which he read from the mass card from the funeral. It was very moving.

He seems to be one celebrity who doesn't get a lot of grief for taking strong stands on controversial issues (he has been arrested a ton of times for no nukes, School of the Americas, etc) and voicing his opinions in interviews. There are a few other long time Hollywood political activists I also admire--Ed Asner and Mike Farrell among them.