The recent success of investment startup Engine No. 1 in securing three board seats at Exxon Mobil Corp. has been called a “watershed moment” for corporate America. The campaign not only represented a David vs. Goliath victory — with Engine No. 1, a 0.02% stockholder, challenging a company of Exxon’s size — but it also constituted the first major shareholder activism campaign with climate and environmental issues playing a critical role, spurring hope that big corporations may be held more accountable for the actions (or lack thereof) they take with regard to ESG issues. In this article for Bloomberg Law, partner Ele Klein and associate Danny Goldstein discuss key lessons from the historic proxy fight that could inform best practices for similar campaigns in the future.