Gerald will appear in the Showtime drama's seventh season as a violent criminal, Entertainment Weekly reports.
He previously played a recurring role on FX drama The Shield and will re-team with that show's creator Shawn Ryan on new ABC thriller Last Resort.
Gerald will also star in forthcoming action movie GI Joe: Retaliation and has appeared on CSI and NCIS: Los Angeles.
Other actors joining Dexter for the new season include Luck star Jason Gedrick - who will play the owner of a strip club - and Rome actor Ray Stevenson - cast as a powerful gangster.
The new season of Dexter will premiere on Sunday, September 30 on Showtime. In the UK, the series airs on FX.
> Dexter casts Katia Winter in seventh season
Watch a teaser trailer for Dexter season seven below: