Mr. Gachui graduated from University of Surrey, Guilford with First Class Honors in Chemical Engineering.

In his professional career he held various positions at Kenya Petroleum Refineries Limited in Mombasa rising to Senior Technologist from an entry-level trainee technologist.

He joined Total Kenya in 1978 and rose to the position of Operations Manager, a role he held until 1985 when he was moved to Paris, France to the Supply and International Trading Department of Total International. In October 1987, he moved to Abidjan, Cote d’Ivoire, as regional trading manager with responsibility for supply and trading for West Africa. In 1991, he returned to Kenya as Manager, Supply, and International Trading, a post he held for three years. He left Total in 1993 to launch Galana Petroleum, a petroleum trading business he co-founded with a former colleague. He retired from the business in 2000.

He is currently involved in business in Kenya and is Chairman of Trans-Century Ltd., Wananchi On Line Ltd. and Jimana Ltd. He is also Director of: Rift Valley Railways (Pty) Ltd., East Africa Cables Ltd, Chase Bank Kenya Ltd, Kewberg Cables and Braids, and Metal Fabricators Zambia Ltd.

His other interests include community development through the Rotary Club. He is currently Assistant Governor for Kenya Central, in Rotary International district 9200 and a board member of Helpage Kenya. He is also Chairman, Enablis East Africa and a keen golfer.