[1] Green is also the co-founder of Treehouse, a company that develops community living apartment complexes in Los Angeles, CA.

He was the co-founder (along with Sean Parker) of Causes, a company most famous for its Facebook app designed to encourage philanthropy and make giving a social experience.

According to a Los Angeles Times story, Green "ran for the local school board when he was 17 and campaigned for a living wage for Santa Monica hotel and restaurant workers.

In 2005, Green started Essembly, a nonpartisan social network that helped connect people with others who shared their political views.

[10] The Causes platform enabled users to create grassroots groups that take action on a social issue or support a specific non-profit organization.

[19][20] Prior to the launch of the group, a controversial private memo prepared by Green for prospective donors was leaked to Politico.

[23] Green is a co-founder and board chairman of Treehouse, a co-living project currently developing community-oriented apartments in Los Angeles.

[26][27] Both Green and Walker found they were happiest in the tight-knit communities of their respective childhoods, so they sought to create a modern version with Treehouse.

[31] Green is an angel investor in several startups, including Asana, Dropbox, FabFitFun, Fin, Lyft, Shift, Manny's and Once Upon a Farm.