In 1968 Sabuni enrolled in the Uganda Army as an officer cadet. He underwent training in Moroto before being sent to the Royal Military Academy Sandhurst in the United Kingdom for further instruction. In 1969 he partook in a three-month long paratrooper course at Malire Barracks in Kampala. He was ultimately commissioned into the army as a second lieutenant. Sabuni still held the rank when Colonel Idi Amin launched a military coup in 1971. Shortly thereafter Sabuni was promoted to the rank of captain. He later attended a company commanders' course at the Kabamba School of Infantry. While there, he was promoted to major. Before he finished the course, he was promoted to lieutenant colonel and attached to Uganda Army headquarters. Shortly after taking up the post Sabuni was made colonel. Several months later he was made brigadier general and appointed Minister of Industry. He also underwent paratrooper training in Israel and for a time served as commander of the Paratroopers Military School in Lubiri. In July 1976 he, in his capacity as Minister of Industry, led a delegation to Japan where they secured a deal with Honda to purchase vehicles for the Ugandan government.