Chouinard has been very good about keeping his involvement quiet but he is long-time partner with Doug Tompkins (The North Face founder) who has been more public about his conservation. Also remember that Kris Tompkins, Doug's wife, is a former CEO of Patagonia. You can further see the personal connection between Tompkins and Chouinard in the film 180 degrees South.
You can read about Tompkins more here:
I want to clarify, I think what Patagonia and all the major companies that use their wealth in some meaningful, if small, way to better the world and environment are doing an great job. From an American perspective they are admirable. However their involvement in other nations tends to be very "american" without the cultural sensitivity needed to effect long lasting change. When american's buy up thousands of acres of foreign land, then donate it for a national park...that's great for the park. It's not great for changing the hearts of a people. Instead they'll always view that land as stolen from them by the outsiders in collusion with the government. It's their land to care for or destroy, not some rich white dude's decision of how best to act as stewards. For a developing nation that needs to exploit natural resources to compete in a global economy, it can be actually used to ensure poverty. Conservation is not the end all be all to environmental problems.
Completely unrelated to Patagonia but the concept is discussed in depth in "The Myth of Wild Africa"