He began hi career at the Ministry of Finance and Economics Planning in Ghana where he worked at the industry, Mining and Forestry Division proir to moving into the Macro-Economic Section of the Ministry. Mr Osei was appointed Ambassador to the United Knigdom and Ireland (2001-2006). Whiles in London, he was elected to the position of Chairperson at the Board of Governors of the Commonwealth Secretariat, UK. As Chief Executive Officer of Ghana Cocoa Board (Cocobod) in 2006, Mr.Osei led the Board to make investments in yeild enhancing schemes, cocoa diseases and pests controls as well as trade logistics infrastructure which saw Cocobod attaining an astounding production target of one million tonnes of coca within three years.
He served as Vice Chair of the Executive Committee of the International Cocoa Organization and was a member of the Consltative Board on the World Cocoa Economy. He served as Chairman of Cocoa Markwtin Company(UK) Ltd and was a member of the Board of Aluworks Ghana Ltd, Cocoa Processing Company Ltd and WAMCO>. He founded Ghanexim Economic Consultanys Ltd and consulted for the World Bank, USAID and Ghana Government on several projects in Ghana. Mr. Osei was also the Managing Director for E.K Osei & Engineers & Contractors Company, as well as Intravenous Infusions Ltd. the largest manufacturers of intravenous infusions and small volume injectables in West Africa.
Currently, Mr.Osei severs as the Board Chairman of Algebra Securities Ltd, Algebra Capital Management Ltd, Ghana Petroleum Mooring Systems Limited and Team Oil Refinery (Managing Director). Mr. Osei represented the Subin Consultancy in the Ashanti Region of Ghana as its Member of Parliament from 2009-2017. he was the ranking member of the Trade, industry and Tourism Committee from 2009-2013, ramking member of the Committee on Foreign Affairs between 2012-2017. He served as a member of the Parliment's House and the Poverty Reduction Committee and Ad-hoc Committee which prepared the Code of Conduct for Members of Parliament, just to mention but a few. He joined the Board of Intravenous Infusions PLC o 16th December 1988.