[2] Johnson was born in Japan, where her father was serving in the United States Air Force; she grew up in Lake Charles, Louisiana.
[1] Originally intending to finish her education there and then work as an engineer, she was inspired to go further by meeting Stanford emeritus professor William Shockley and reacting to his racist beliefs about the intellectual inferiority of African-Americans.
[5] She went to Rice University for doctoral study in electrical engineering, advised by Fayé Briggs, an immigrant from Nigeria.
[1] She completed her Ph.D. in 1988 with the dissertation The effects of cache coherence on the performance of parallel PDE algorithms in multiprocessor systems.
[1][4] By 2001, she had become a manager of a web–database integration team in IBM's Silicon Valley Lab in San Jose, California,[4] and in 2011 she shifted from research and development to become a business development executive and later Chief technology officer of IBM Central, East and West Africa, and was based in Nairobi, Kenya.