She has appeared in dozens of television series and had featured roles in films such as A Guide for the Married Man and The Cheyenne Social Club, both directed by Gene Kelly, as well as The Rounders opposite Henry Fonda and Glenn Ford and two Elvis Presley movies, Roustabout and Frankie and Johnny.

Langdon's first regular role on network series television came as the third actress to play Alice Kramden in Jackie Gleason's The Honeymooners sketches and shows.

A premature departure from the role following a brief four-week run left her mark on the American Scene Magazine era of Gleason's career a small one at best.

In another popular situation comedy, Langdon played a scatter-brained defendant on trial in a Dick Van Dyke Show episode called "One Angry Man".

Her other guest appearances on TV programs included Gunsmoke, Tales of Wells Fargo, 77 Sunset Strip, Bourbon Street Beat, Room for One More, Shotgun Slade, Mannix, Thriller, Bonanza, Ironside, McHale's Navy, The Man from U.N.C.L.E., Banacek, The Wild Wild West, Hart to Hart, Three's Company, The Love Boat, and Happy Days, and as herself on Rowan and Martin's Laugh In.

Langdon portrayed Lillian Nuvo, the wife of a loading-dock foreman turned corporate executive, and won a Golden Globe award for her performance.

[8] Grandpa Goes to Washington, an NBC hour-long comedy starring veteran actor Jack Albertson, featured Langdon as Rosie Kelley, the daughter-in-law of an over-65 maverick United States senator.

Premiering in 1978 opposite Happy Days and Laverne and Shirley, the top-rated block of shows at the time, her third attempt at weekly episodic television lasted four months.