Devon Gummersall (Mad Men) and Mykelti Williamson (Justified) have landed roles in Underground, WGN America’s pre-Civil War series about the Underground Railroad. The series from Sony Pictures TV and Tribune Studios follows a group of slaves who plan a daring escape from a Georgia plantation to cross 600 miles to freedom. They are aided along the way by a secret abolitionist couple running a station on the Underground Railroad, as they evade those tasked with bringing them back — dead or alive.

Gummersall is set to play the series regular role of John Hawkes, a lawyer and abolitionist who is trying to reconcile the way things are with the way things should be. Repped by Don Buchwald and Associates and GEF Management, Gummersall has a role in the current final season of Mad Men, and his recent credits include iZombie, The Mentalist and CSI.

Williamson will recur on Underground as Moses, a fiery preacher for the slaves on the plantation who decides to take his family on the run. Along with recurring as Limehouse on Justified, his recent credits include Hawaii Five-O, Nashville and 24. He is repped by Paradigm, Frontline Management and Myman Greenspan.