In 1980, he co-founded the Washington, DC-based lobbying firm Black, Manafort, Stone with principals Paul Manafort and Charles R. Black Jr. It recruited Peter G. Kelly and the firm was renamed Black, Manafort, Stone and Kelly in 1984. During the 1980s, BMSK leveraged its "White House connections" to attract "high-paying clients" including "U.S. corporations", "trade associations", and foreign governments. By 1990, it was "one of the leading lobbyists for American companies and foreign organizations".
Stone has variously been referred to in media as a "political dirty trickster", a "renowned infighter", a "seasoned practitioner of hard-edged politics", and a "veteran Republican strategist." Over the course of his political career, Stone has been widely regarded as promoting a number of falsehoods and conspiracy theories. Stone is the subject of a Netflix documentary film, titled Get Me Roger Stone, which focused on his past and role in the 2016 presidential campaign of Donald Trump. Stone officially left the Trump campaign on August 8, 2015; however, two associates of Stone have claimed that he collaborated with Wikileaks owner Julian Assangein the spring of 2016 to discredit Hillary Clinton's campaign.