As most of the martyrs Kiwanuka was a Muganda from Lugave clan. His father was Kyazze and his mother was Nassazza Talidda of the Civet-cat Clan.

He was born at Luagala near Ssingo County. As Kiwanuka’s father was a deputy County Chief for a long time due to efficiency, the son became famous like his father and a gate keeper of Mukwenda.

At the age of fifteen, Kiwanuka was selected to go and serve King Mwanga II as a page. He went with cousins and took witchcraft for their protection but on arriving, they were converted to Catholicism by their elder Charles Lwanga, convinced and they burnt all witchcraft. But their parents and relatives threw them out of the Clan.

Kiwanuka worked in the audience hall. But whenever he had a chance during his free time, he could learn how to read and write. Sometimes he served as a messenger.

He was also baptised on Monday night 16^th May, 1886 at the age if seventeen. Achilles is patron of journalists, press writers, printers and artists.