[1] Sewankambo was educated at Namilyango College, an all-boys residential middle and high school (grades: eight to thirteen) located in Mukono District, from 1965 until 1970.

He later obtained a Master of Science degree in Clinical Epidemiology, from McMaster University in Hamilton, Ontario, Canada.

[1][3][4] In the early 1980s, Sewankambo was one of the earliest physicians in Uganda to recognize the new disease that caused patients to lose weight and "slim" down to abnormal cachectic sizes.

He has been at the forefront of research about the disease, specializing in HIV clinical drug trials.

[5] He has extensively published the finding of his research in medical journals and other peer publications.