The drama, which stars Alexandra Breckenridge, focuses on two young female detectives who are as comfortable discussing fashion and pop culture as they are solving cases.
Deadline says that Smith has now signed up to play a vice detective who is transferred to Cooper and Stone's precinct after his cover is compromised.
His character is thought to have known Stone at the police academy and the duo have a difficult relationship, although there are suggestions that there could be sexual tension between the pair.
Smith played Kyle in 24 and has also appeared in shows including Freaks And Geeks and Joan Of Arcadia. He recently had guest roles in episodes of Leverage and The Closer.