 He was admitted to Makerere University to study Law.However, in 1985, at the age of 20, he left Makerere to join the National Resistance Army (NRA), in their guerrilla war against the Obote II regime (1980–1985) and the military junta (1985–1986) that ousted him.After the NRA captured power in 1986, Mayombo returned to the university and finished his law degree, graduating with a Bachelor of Laws (LLB).