The drama series stars Claire Danes as a CIA agent who believes that the American Marine (Damian Lewis) they rescued from Al-Qaeda after eight years of being held prisoner was turned by the terrorist group and is now a threat to the US.
Negahban will continue to play terrorist Abu Nazir on the second season, while Marciano is upgraded to a "full-time cast member" as the surveillance expert Virgil, reports TV Line.
Last year, Homeland was renewed for a second season after its well-received debut season.
"Clearly, the overall audience growth from week one to week four demonstrates that this show is hitting a nerve in the cultural zeitgeist," said David Nevins, Showtime's president of entertainment.
President Barack Obama even named the drama series as one of his favourite shows.
Watch a video clip of Homeland below: