The 51-year-old actor is the co-founder of Prairie Pulp & Paper Inc., which launched its brand of environmentally friendly paper Wednesday.
The company spent 15 years researching and developing its Step Forward Paper. It's made of wheat-straw waste and wood fiber rather than virgin trees.
The company says replacing two packs of traditional copy paper with their product saves one tree.
Harrelson says half the world's forests are cut down to make paper, and his company's new paper is "going to be great for our future."