[2] Mason played the role of Nikki Bell, a Braille teacher who became the title character's business partner,[3] in the television series Longstreet (1971-1972), which starred James Franciscus.

[4] Her other acting credits include roles in Hogan's Heroes, My Three Sons, Burke's Law, The New Phil Silvers Show, Kentucky Jones, Bonanza, The Big Valley, Ben Casey, Dr. Kildare (in a recurring role), Laredo, Occasional Wife, The Man from U.N.C.L.E., I Spy, , The F.B.I., Mission Impossible, The Fugitive, Mannix, Vega$,The Invaders, The Odd Couple, Love, American Style, Marcus Welby, M.D., Cannon, Barnaby Jones, Gomer Pyle, U.S.M.C., Wonder Woman, The Bronx Zoo, Charles in Charge, Ironside, Jake and the Fatman, and in the episode "The Mask of Adonis" from the 1977 series Quinn Martin's Tales of the Unexpected (known in the United Kingdom as Twist in the Tale).

Margo Demarest in Twelve O'Clock High Season 3, Episode 9 "The Fighter Pilot"[citation needed] Mason played a principal role in the original 1967-68 Broadway production of How Now, Dow Jones.

In 2019, she starred in the feature film Senior Love Triangle as the character Jeanie.

[6] She appeared in such television movies as That Certain Summer, Outrage, Attack on Terror: The FBI vs. the Ku Klux Klan, Last of the Good Guys, The New Adventures of Heidi, My Wicked, Wicked Ways: The Legend of Errol Flynn, and Fifteen and Pregnant.