Erivo, playing Poins and the Earl of Douglas, joins the previously announced Harriet Walter, who previously starred in Lloyd's all-female Julius Caesar, in the title role.
The cast is completed by: Ashley McGuire (Falstaff), Elizabeth Chan (Northumberland/Peto, Jackie Clune (Westmorland/Glendower), Shiloh Coke (Mortimer), Karen Dunbar (Vernon/Bardolph), Zainab Hasan (Hostess), Ann Ogbomo (Worcester), Katie Robinson (Messenger) and Sharon Rooney (Lady Percy/Gadshill).
Lloyd's production will encompass action from both Henry IV Part I and Part II to create "a single narrative of Shakespeare's monumental history plays".
The Donmar is once again collaborating with Clean Break theatre company, who work with women whose lives have been affected by the criminal justice system.
Lloyd said: "We have been amazed by the explosive reaction to women being given a crack at these jewels in our dramatic crown... The collaboration with Clean Break has been fundamental."
Henry IV runs at the Donmar from 9 October to 29 November 2014 (previews from 3 October), after which it will play a week's residency at Mulberry School for Girls in Tower Hamlets.
Kate Pakenham, executive producer at the Donmar, said: "Phyllida Lloyd is one of this country's major theatre artists. Her vision around Julius Caesar was revelatory and it is a thrill to have her return with Henry IV and embark upon the second production in this three-part project.
"By taking the production to Mulberry School for Girls, and the accompanying education and outreach work, we have a chance to extend this mission beyond the walls of the Donmar."