[1] After graduating with a diploma in teaching from Makerere University, Eddah joined Thika High School in 1960 and taught for 3 years.
Subsequently, she was appointed Head of the General Methods Section at the Kenya Institute of Education with a focus on Curriculum Research and Development where she served between 1965 and 1968.
[2] Between 1993 and 1998, Eddah was the Founding Executive Director of the Forum for African Women Educationalists (FAWE).
Eddah's husband Daniel left his job at the East African Industries (now known as Unilever Kenya) to launch the primary school business.
Eddah is married to Daniel K. Gachukia, Chairman and Co-founder of the Riara Group of Schools.