With two colleagues from Donaldson, Lufkin & Jenrette and subsequently
Credit Suisse First Boston, Bennett Goodman and Doug Ostrover, Smith founded GSO Capital Partners in 2005; its name derives from their initials. He continued at GSO after its acquisition by Blackstone in 2008, serving as managing director He is a non-executive director of English football club
West Ham United since purchasing a 10% stake in 2017. In 2020, there were rumors that he was forming a consortium to purchase a controlling interest in the club. In 2021, following
Daniel Křetínský's purchase of a 27% stake in West Ham, Smith's shares were reduced to 8%. ==Personal life==