Seyi is a graduate chartered accountant. After receiving a first degree in Economics in 1981, he began a professional accounting career at PricewaterhouseCoopers and then worked in corporate
banking for several years before joining the housing association movement at Housing 21 in 1995.

After a spell in a range of social housing provisions, from elderly housing through to all forms of supported housing, Seyi joined Centrepoint in 2003 as its finance director. He became Centrepoint's first chief operating officer in 2006 and chief executive in 2009. In this time, he has developed a passionate concern for disadvantaged young people, especially those that are homeless. In his role as chief executive, Seyi takes overall responsibility for moving Centrepoint towards its vision of ending youth homelessness.

Seyi is the volunteer treasurer on the board of Foundation 66, an organisation that offers holistic treatment and support to people with problematic alcohol and drug use, their carers and families.

He also sits as a commissioner on the National Inquiry into Lifelong Literacy and previously served as a commissioner on the Family Commission, a national inquiry into the extended family and the
support it needs in the 21st century.

He is currently serving as a Commissioner of the UK Commission for Employment and Skills (UKCES) and as Trustee of Sutton Christian Centre. Previously, he served as a Commissioner of the Family
Commission - a national inquiry into family life and the support families need in the 21st century, on the NIACE National Commission of Inquiry into Lifelong Literacy, as a Trustee/Chair of Finance Committee of Foundation 66 and as a Board member/Chair of Finance Committee of Clapham Park Homes.