Born in Barry, Forfarshire, Kirk studied medicine at the University of Edinburgh, graduating in 1854. He then served as assistant physician in the Crimean War in 1855. In 1857 he was appointed to accompany Dr. David Livingstone on his Zambezi expedition. The numerous photographs that Kirk took whilst away provide an intriguing and valuable record of the expedition. Kirk remained an admirer of Livingstone’s work and later became Consul-General at Zanzibar where he was instrumental in stopping the African slave trade. In 1882 he was awarded the Royal Geographical Society’s Patrons medal. He received numerous other accolades.