[1] Nantulya was born on 15 January 1949 at Bulayila Village, in present-day Kibuku District, the son of Brenda Kirangi and Paulo Mukatabala.
[1][2] After internship at Mulago National Referral Hospital, back in his native Uganda, Nantulya won a scholarship to study outside the country and specialize in Immunology.
[1][2][3] After his internship at Mulago Hospital, Nantulya was employed as a teaching assistant at Makerere University School of Medicine.
In 2002 he was appointed as senior health adviser at The Global Fund to Fight AIDS, Tuberculosis and Malaria, in Geneva.
[1] Nantulya served on the selection committee that chose Peter Sands to succeed Mark Dybul as executive director of the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) in 2017.
[6] Nantulya developed a vaccine called Kuku Star, that prevents New Castle Disease in chicken.