A role he and I had in racial segregation (9)
I believe the answer is:
apartheid
'racial segregation' is the definition.
('apartheid' can be a synonym of 'racial segregation')
'a role he and i had' is the wordplay.
'role' becomes 'part' ('part' can be a synonym of 'role').
'and' is a charade indicator (letters next to each other).
'i had' becomes 'id' (I'd).
'a'+'part'+'he'+'id'='APARTHEID'
'in' is the link.
(Other definitions for apartheid that I've seen before include "former South African segregation system" , "form of rule" , "regime" , "Former South African system of racial separation" , "System of segregation formerly practised in South Africa" .)