Carpenter filed for divorce Thursday, hours after Hall received a Screen Actors Guild nomination for best actor.
The couple were married on Dec. 31, 2008, and Carpenter's filing says they separated in August.
She cited irreconcilable differences for the breakup, but court filings provided no additional details. The two have no children together.
Carpenter is seeking spousal support from Hall, who plays Dexter Morgan, a serial killer who targets other murderers on the hit Showtime series. The show just concluded its fifth season and has been renewed.
Publicists for Carpenter, Hall and Showtime did not comment Thursday on the divorce or how it may affect the show.
Carpenter plays Hall's sister, a Miami police detective who is often on the trail of her brother's victims, but does not know he is a killer.
Hall, 39, first earned famed for his role on the HBO series "Six Feet Under," which concluded in 2005.
He won a best TV drama actor SAG award in January and thanked Carpenter during his acceptance speech. His win came while he was battling Hodgkin's lymphoma, a cancer that attacks the lymph nodes. Carpenter, who turns 31 on Friday, said in April that Hall had "fully recovered."