Entertainment Weekly says that the actor, who played Chris Partlow in The Wire, has landed a major recurring role in the series.
His character joins the show as a new temp nurse and is described as good-looking, popular and qualified.
Akinnagbe will make his debut in the middle of the third season and has agreed to star in at least seven episodes.
He has recently had guest roles in shows including The Good Wife, Dark Blue, Fringe and Law & Order: SVU.
The third season of Nurse Jackie is expected to begin on Showtime early next year.