Sarah Adebisi Sosan was born in Lagos 11 February 1956 to the aristocratic family of Chief and Princess Durosinmi of Irewe town in Ojo Local Government Area, Badagry division. Her mother hails from the Fafunwa Onikoyi Royal Family of Ita-Onikoyi in Idumota, Lagos Island, and her father was a member of the defunct Action Group (AG) and Unity Party of Nigeria (UPN), thus making him a long-time disciple of Obafemi Awolowo. Due to her maternal ancestry, she  bears the Yoruba traditional title Omoba (Princess).

She began her early education at the Unity Assembly Primary School Apapa and Secondary Education at the Awori-Ajeromi Secondary School, Lagos. She commenced her sojourn in the teaching profession at the then Lagos State College of Education, Ijanikin (now Adeniran Ogunsanya College of Education) in 1980 where she obtained the National Certificate of Education (NCE) and later proceeded to the University of Lagos, Akoka, where she obtained her Bachelor of Arts in English Education (B.A) Ed in 1988 and a Master’s degree in Adult Education ( M.Ed ) 1989.

As a Youth Corper, Bisi taught at the St. Leo’s Secondary School Abeokuta, Ogun State as a classroom teacher while her sojourn in the Lagos State Public Service started in January 1989 when she was employed by the then Lagos State Post Primary Teaching Service Commission ( PP- TESCOM ) as a Master Grade II, a classroom teaching appointment.
Between 1990 and 1999, Mrs. Sosan left the classroom and served as a Principal Education Officer at the Lagos State Ministry of Education and then moved to the defunct State Primary Education Board (SPEB) now Lagos State Universal Basic Education Board (LSUBEB) as an Assistant Board Secretary. Later in year 2006 when the state Primary Education Board transformed to Lagos State Universal Basic Education Board, she was redeployed to the Department of Communication and Information Technology as the Head of Department (HOD). As the Head of Department, she was saddled with the responsibility of ensuring computer education and training was given the attention it deserved in Lagos State Public Primary Schools. She was the running mate to Mr Babatunde Raji Fashola when he contested as Governor of Lagos State in 2007.

She served as  Deputy Governor of Lagos State from May 2007 – May 2011, a position she combined with serving as Commissionerfor Education. During her tenure, she was also responsible for Local Government and Chieftaincy Affairs. She continues to work in the education field and on charitable initiatives. She is a devoted wife to Commander Oluseyi Sosan and mother of three children.