The 41-year-old actor will play Dr Gilbert Mason, a civil rights activist who takes non-violent action against segregation in the early 1960s, Deadline reported.
Mason's protests changed history with the first successful anti-discrimination suit filed against the state of Mississippi.
'A Civil Right' comes from Salvatore Stabile, who will serve as both writer and director of the biopic.
Casting for the Revolution Media-produced feature is still ongoing.
Ealy is best known for his role as Dorian in the US version of 'Almost Human'. The series was cancelled by Fox back in April.