Mwanje has over 20 years of experience as a transformational leader in agri-food systems, public policy, partnership management, community development, school feeding programming, grant development and partnership agreements management as well as a good blend of national, regional and global development and intercultural linkages. His training, multiple experiences, specialization, research, and developmental interests are in strategic management, organizational change, organizational development as well as agricultural sector policy planning and development. The rich experience spans public and private sectors. The private sector activities include working with multicultural INGOs, collaborating with vulnerable groups such as children, women, youth, smallholder farmers, and local churches. This involved overseeing initiatives in 660 primary schools, 354 local churches, school committees, government departments, 720,000 smallholder farmers, and overseeing various projects in food security, holistic child development, school feeding, water projects, building the capacity of school management committees, establishing 4-K clubs, facilitating market linkages, coordinating research with USA Universities such as Harvard, California Berkeley, and representation of the organizations.

In addition to having been a county executive committee member for agriculture, livestock and fisheries, and chair of the CECM caucus and co-chair of the intergovernmental sector working group, he has established donor and private sector relations including with the World Bank, IFAD, The Rockefeller Foundation, AGRA, WFP, Christian Aid, Acorn Rabobank, The New York Botanical Gardens (NYBG), Bayer, OCP, Care Kenya, ICS Africa, Compassion International, Absa Bank, IRRI, AATF, among others.

Public sectors experience spans being a county executive committee member for agriculture, overseeing public engagements, developing, and lobbying for policies, and chairing intergovernmental sector working groups between the county and national governments. These were on policy formulation and implementation efforts, negotiation, being members of project steering and implementation committees.

Dr. Osia holds a PhD and MBA degrees in strategic management from Jomo Kenyatta University of Agriculture and Technology and a Bachelor of Science Agriculture degree from Egerton University, Njoro. He has obtained certification training business process engineering, master community facilitator, and public sector administration from Ordu University, Türkiye, Eastern and Southern Management Institute (ESAMI), the Kenya school of Government and Global University for Lifelong Learning (GULL).