A Kenyan national, he started writing newspaper articles in 1999 while still in college. Since then, he has remained a freelance science journalist focusing on environmental issues, health, agriculture and technology. Isaiah has published articles in a wide range of print and online publications within Kenya as well as internationally – include Reuters AlertNet, Inter Press Service, SPORE (CTA) Magazine, the UK-based New Internationalist, Kenyan Daily Nation newspaper, The East African, The Standard, Kenya News Agency, People Daily, and AgroLink, among others. Together with five other journalists, Esipisu has published a photography book titled ‘The Kindest Cut’ featuring Male Circumcision as a preventive measure against to HIV infection.