O'Connor is probably best known as the leader of the National Toxics Campaign, a ground breaking effort he founded in 1983 to raise consciousness about the deadly impact of abuses perpetuated by unregulated chemical companies. O'Connor later became the chairman of Gravestar Inc., an assets management company with a mission to stay committed to the environment and the community. In 1991, he also founded Greenworks, a company that "incubates" environmental start-up companies. O'Connor engaged in the game of progressive politics with the zeal of a Boston pol, which he eventually became, running for Congress in 1998. O'Connor was married to Carolyn Mugar, an heir to the Star Market fortune, who is a long time activist and organizer of Farm Aid and a close collaborator with famed musician Willie Nelson.