Johnson was born in Hickory, Mississippi. He was the ninth of 10 children born to Archie and Edna Johnson. Johnson studied history at the University of Illinois and graduated in 1968 with a bachelor's degree. He earned a master's degree in public administration at Princeton University in 1972.
Johnson worked at the Corporation for Public Broadcasting and the Washington Urban League before becoming press secretary for Walter E. Fauntroy, who was the congressional delegate from the District of Columbia. He moved from that position in 1976 to serve as vice president of government relations for the National Cable & Telecommunications Association (NCTA), a trade association representing more than 1,500 cable television companies. In 1979, he left NCTA to create BET, the first cable television network aimed at African Americans, which launched in January 1980, broadcasting for two hours a week. Eleven years later, BET became the first black-controlled company listed on the New York Stock Exchange. In 1998, Johnson took the company private, buying back all of its publicly traded stock. A year later, Viacom bought BET for $2.3 billion in stock. Johnson continued to be the company's chairman and CEO. He also serves on the boards of U.S. Airways, General Mills and Hilton Hotels. Johnson is also the first African American to be the principal owner of a North American major-league sports franchise; he leads the group that acquired the Charlotte Bobcats NBA expansion franchise. The Bobcats will begin play in the fall of 2004.
BET reaches more than 65 million U.S. homes and has expanded into other BET-related television channels, including BET International, BET Jazz, and BET hip- hop. BET is now one of the major cable television networks.