The drama, set in the early 1800s, follows a group of travellers who embark on a dangerous cross-country journey.
Jensen has now joined the cast as Dr. William Strong, The Hollywood Reporter says.
The actor has previously starred in shows such as Love Monkey and CSI, while more recently he has had guest spots in 30 Rock, It's Always Sunny in Philadelphia, Leverage and NCIS: LA.
Jensen's casting comes after Bridget Regan, Ethan Embry, Jake McLaughlin, Megan Ferguson, Gina Bramhill and Al Weaver all signed up for roles in the pilot for The Frontier.
The project is being directed and executive produced by Thomas Schlamme, whose previous credits include Pan Am, The West Wing, Studio 60 on the Sunset Strip and Mr Sunshine.
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