He was born on 2 March 1957 in Lagos State to late Chief Julius Kosebinu, a banker and Mrs. Margaret Olabisi a teacher. He is the second child and first male child of five children including Segun Agbaje, CEO of Guaranty Trust Bank.
In a 2013 interview with The Punch Newspaper, Agbaje talked about how he began in politics: "It had to do with the Moshood Abiola/Bashir Tofa presidential election", he said. "I saw the annulment as a personal insult and an assault on the Nigerian people. This led to my first entry into what I would call activism, working with other concerned professionals" such as Prof. Pat Utomi, Dr Ayo Ighodaro, Asue Ighodalo, Billy Lawson, Oby Ezekwesili, Tola Mobolurin and Hassan Odukale. Jimi was in one form of resistance group or the other which ultimately led him to join the socio-political organization, Afenifere where he served as national treasurer. Based on his affiliation with , Jimi Agbaje joined the Action Congress - his first political party. In 2007, Agbaje who had initially aspired to contest for the Governor of Lagos State on the platform of the Action Congress left the party to join the Democratic People's Alliance. He was among the 11 aspirants that turned their back to the Action Congress when it was alleged that Governor Bola Tinubu had already anointed someone else to succeed him even before the party primaries. Widely believed to have conducted the best campaign in 2007, Agbaje contested in gubernatorial election on the Democratic People's Alliance platform, but eventually, alongside other major contenders - Musiliu Obanikoro of PDP, Femi Pedro of Labour Party - lost to Babatunde Raji Fashola of the Action Congress. He left DPA in 2011 and went on to join the ruling party, the People's Democratic Party, PDP following the de-registration of DPA by the Independent National Electoral Commission. On 29 October 2014, he officially indicated his interest in giving the Lagos State gubernatorial elections another shot by picking up the PDP nomination form. On 8 December 2014, it was reported that he emerged as the candidate of the People's Democratic Party, PDP for the 2015 Lagos State gubernatorial election, having defeated Musiliu Obanikoro in the primary. Musiliu Obanikoro is the former Minister of State for Defence who is also a member of the opposition party, People's Democratic Party, PDP. In October 2018, Jimi Agbaje secured the PDP's ticket to run for the office of the governor of Lagos state. He defeated Adedeji Doherty to secure the ticket. Jimi Agbaje lost to Babajide Sanwo-Olu of the All Progressives Congress, in the Lagos state gubernatorial election on 9 March 2019.
Official duties
He has held various professional positions. Among others are:
National Secretary Nigerian Association of General Practice
National Chairman of Nigerian Association of General Practice Pharmacists
Merit Award Winner, Pharmaceutical Society of Nigeria
Fellow, Pharmaceutical Society of Nigeria
Fellow, West African Post Graduate College of Pharmacists
Personal life
He is married to Abiola Agbaje, a lawyer. The couple met as students at the University of Ife, now Obafemi Awolowo University and dated for eight years before getting married. They have three children; two boys and girl.