Johnson joined ABC News in 1968, ultimately becoming the first African American documentary producer, director and writer at a broadcast network. He won distinction for his documentaries "Welfare Game" and "Strangers in Their Own Land: The Puerto Ricans." He was one of the first black filmmakers in the prestigious Directors Guild of America. Johnson then became a network correspondent and covered such stories as the Attica Prison riot that led to the deaths of 33 prisoners and 10 corrections officers.