Jens appeared in the April 7, 1962, episode of The Defenders, “The Naked Heiress”, where she portrayed a college educated stripper romantically involved with a much older professor who, in a drunken state, was tricked by her conniving mother into changing his will, making Jens’s character the heir to his entire estate. In 1963 she appeared in an episode of The Untouchables, “The Man in the Cooler,” an episode of The Outer Limits, “Corpus Earthling”. In 1966, she played a WWII nurse of Nazi Germany assigned in Northern Africa in The Rat Patrol episode entitled, “The Blind Man’s Bluff Raid”, which aired October 24, 1966. Other appearances in other television shows included I Spy episode “A Room with a Rack” in 1967, as a globe-trotting pilot friend of Kelly Robinson and Alexander Scott. She was cast as a prisoner in “The Wagon”, a 1970 episode of Bonanza.

In 1971, she portrayed a widow with two children in the Gunsmoke episode, “Captain Sligo”, with Richard Basehart in the title role as an Irish cattle buyer who courts her. In 1974 she guest-starred in an episode of McMillan and Wife, “Reunion In Terror”, and on The New Land. She appeared on Gibbsville in 1976. In 1976–77 Jens played the role of Mae Olinski on the soap spoof Mary Hartman, Mary Hartman. She appeared on the scripted talk show Meeting of Minds, hosted by Steve Allen (S03E05 and S03E06, 1979), portraying Empress Theodora.

In 1986 she appeared in The Colbys, Cagney & Lacey, and MacGyver. She appeared in several episodes of Falcon Crest (1987) and The Hogan Family (1989), and in a 1990 episode of The Wonder Years. Jens played Clark Kent’s mother Martha Kent in several episodes of the TV series Superboy (1988-92). In 1992-93 she appeared in a three-episode arc of season 7 of L.A. Law. She appeared as Joan Campbell in several episodes of Melrose Place in season 1 (1992-93) and again later in an episode of season 6 (1997).

Jens appeared in the 1993 episode of Star Trek: The Next Generation, The Chase, as a member of the race responsible for populating the galaxy with humanoid lifeforms, and had a recurring role spanning 5 seasons of Star Trek: Deep Space 9 as the totalitarian Female Changeling (1994-99).

Jens narrated a number of documentaries including The Great War and the Shaping of the 20th Century and the 1986 film, The Clan of the Cave Bear. She voiced the female Guardian in the Green Lantern movie (2011). In 2018, Jens lent her voice to the video game Star Trek Online, reprising her role as the Female Changeling.