Clarke read about the AIDS epidemic in Uganda and decided to come see for himself. He was taken to Kiwoko Village in present-day Nakaseke District in the Luweero Triangle. He arrived in 1987, at the tail end of the Ugandan Bush War, which he had been unaware of until he arrived. He subsequently returned with his family under the auspices of the Church Mission Society to work in Kiwoko. Clarke initially treated his patients under a tree before going on to establish Kiwoko Hospital which, as of March 2015, maintained a nurses training school, a laboratory technician training school, a large community health programme, a neonatal ICU, and full general hospital facilities. Clarke later moved to Kampala, setting up his first clinic within the Kampala Pentecostal Church Building on Buganda Road in Central Kampala. His vision continued to grow and he subsequently opened International Hospital Kampala in Old Kampala where the first open heart surgery was carried out. IHK subsequently grew and moved to Namuwongo, another Kampala suburb. The 110 bed facility is the only ISO certified hospital in Uganda and strives to continue bridging the gap in private healthcare provision in Uganda through providing quality, affordable healthcare. The hospital has state-of-the-art facilities including specialties such as obstetrics and gynecology, pediatrics, and plastic surgery.
Other responsibilities
Clarke also writes a weekly column in The New Vision, Uganda's biggest daily, and has penned two books entitled The Man With The KeyHas Gone and How Deep Is This Pothole. He has further projects in Juba, South Sudan and in Zanzibar, Tanzania where his family built, owns, and operates a boutique hotel. His wife Roberta Clarke, lives with him in Kampala. Their oldest son Sean oversees the approximately 12 clinics that his father owns in Uganda. Their daughter Lauren is a nurse and lives in Ireland. Their youngest son Michael runs the family hotel in Zanzibar.
Political career
In November 2010, Clarke entered Ugandan politics by securing nomination, as an independent candidate, to contest for the chairmanship of Makindye Division, one of the five divisions of the Kampala Capital City Authority, the governing body of Uganda's capital city of Kampala. He was motivated to run due to the bad roads and poor living conditions within his community. His three pillars in the election were: "good roads, good health and economic development". He enjoyed a landmark victory and was sworn into office as mayor in May 2011 to serve for a five-year term.