He served until his death as the Nigerian ambassador to Spain, a position he assumed in January 2021, with concurrent accreditation as a permanent representative of Nigeria to the United Nations World Tourism Organization (UNWTO).
He also attended Harvard University's John F. Kennedy School of Government, where he completed a Senior Executive Education and earned a certificate in National and International Security.
On returning to Nigeria,[4] Seriki joined Equity and Trust Finance Company Limited, from 1987, as business manager until he was appointed chairman of the Lagos State Sports Council in 1992; a position he held until 1994.
In spite of the political instability, Seriki was instrumental in engaging young talent in sporting activities at the state and national levels.
He was granted Honorary Life Membership in the Table Tennis Association in 1993, in recognition of his public administration expertise and passion for sports development in Lagos State.
With the Nigerian military due to hand over power (which they ultimately failed to do) in 1993, to elected civilians, Seriki left public service to start the Perpetual Investment and Finance Company Limited (PIFCO), as well as to launch a career in politics.
In 1992, Seriki was the senatorial candidate for Lagos Central District constituency, on the platform of the defunct National Republican Convention (NRC) In 1998, he was elected a member of the federal House of Representatives from the Lagos Island federal constituency on the ticket of the defunct United Nigeria Congress Party (UNCP).
His political vision aimed to ensure quality education for youths in the rundown areas of his senatorial district, by gaining the support of the federal government through special federal government support schemes, to rejuvenate literacy in such densely populated parts of Lagos State described by him as the most cosmopolitan and populated in Nigeria.
He chaired the Nigerian Civil Defence, Immigration, and Prisons Services Board and assisted in overseeing areas such as coordinating and ensuring harmony with the ministry's mandate.
Under Seriki, there was effective oversight of the operations of the Armed Forces Resettlement Scheme and the welfare of ex-service personnel—including the Nigerian legion.
Finally and significantly, he was responsible for the supervision of the joint services organisations and parastatals, such as the Nigerian Defence Academy, Armed Forces Command and Staff College, National War College, Defence Industry Corporation of Nigeria (DICON), Nigerian Armed Forces Resettlement centre (NAFRC), and the Tafawa Balewa Square Investment Limited.
[10] He undertook various national initiatives through his supervision of the privatization of federal government enterprises in the solid minerals, steel, and aluminium industries.
He advised the federal government on key matters relating to policy formulation and implementation to realize set growth indices in such industries.
During this, Seriki's first appointment to national service, he worked alongside the minister in setting out policies on the agriculture and water resources needed to galvanise the employment, industrial, and social development of this sector of the Nigerian economy.