After the completion of his primary and secondary education, he went to the prestigious University of Ife now Obafemi Awolowo University in 1985 where he bagged a degree in Agriculture. He thereafter proceeded to the pioneer University of Ibadan where he received his Masters and Doctorate Degree in 1987 and 1993 respectively in Agronomy with specialization in farming systems, soil survey, land use planning and pedology.
Dr. Onasanaya has been in leadership positions for the past 15 years where he has been able to mentor some staff of Government from being an Assistant Director and the Head of Agricultural Extension Services Component at the Lagos State Agricultural Development Authority, a parastatal of the Lagos State Ministry of Agriculture and Cooperatives where he supervised over 115 extensions officers. In 2005, he was given a special assignment as the State Project Coordinator of the successful World Bank Assisted Project, the FADAMA II. During his time, Lagos State contributed 80% of the entries which made the project won the Regional Excellence Award for Africa presented by the World Bank.
He was promoted to a Deputy Director in 2008 and also nominated to anchor the FADAMA III project. He later left the FADAMA III project to resume as the Head of the Agricultural Services Department in the Ministry, a total of 120 FADAMA Community Associations and 1200 Fadama Users Froups have benefited from the project in Lagos State in 2011.
In 2012 when he became a full Director of Agricultural Services, several laurels were recorded and this eventually led to his appointment in 2016 as a Permanent Secretary in the Lagos State Civil Service. Dr. ONasanya, working under His Excellency the Governor of Lagos State, Mr. Akinwunmi Ambode has been instrumental to the emergence of the successful Lake Rice, a 100% Rice produced in Nigeria amidst other projects.
He is happily married and blessed with good children.
He attended Army Children High School after which he proceeded to the prestigious University of Ibadan for his first degree and Masters programme in Crop Protection and Environmental Biology.