After completing his secondary education, he worked at the Federal Survey Department as a third class clerk under his boss the late Mr. Ojemuyiwa of Isara-Remo.
Oyesanya became an Editor of the Daily Service paper (now defunct), and won a Federal Government scholarship in 1952 to further his training in Journalism at the Royal Polytechnic Institution in London (now known as Westminster).
On 15 March 1954 the inaugural meeting of the NUJ was held at St. Paul’s School, Breadfruit Lagos, Nigeria and a resolution was passed forming the organization.
Oyesanya joined the Federal Ministry of Information in 1958, and was posted to the Nigerian High Commission in London to assist in establishing the Department of External Publicity.
This was penultimate to his appointment as the Secretary-Registrar and Chief Executive of the Nigerian Press Council in 1979, where he played a principal role in making it acceptable to member organizations.