[2] She made guest appearances on many television series, including the ABC/Warner Bros. programs 77 Sunset Strip and Maverick, CBS's Have Gun - Will Travel, and the crime drama Richard Diamond, Private Detective.

Barnes appeared as Kate Henniger, with Bing Russell and Arthur Space in the 1958 episode "Ghost Town" of the ABC/WB Western series Colt .45, starring Wayde Preston.

In the 1960s, Barnes worked for producer Martin Ransohoff and appeared in episodes of his The Beverly Hillbillies ("Elly Goes to School" and "The Clampett Look") and was billed as special guest-star.

Barnes played Peter Falk's former wife on the 1965–1966 CBS series The Trials of O'Brien[8] and was host of the ABC daytime talk show Dateline: Hollywood in 1967.

Among her most remembered roles is the snooty Gloria Upson in the film Auntie Mame (1958), which earned her a Golden Globe Award nomination for New Star of the Year.

In Disney's original 1961 version of The Parent Trap starring Hayley Mills, Barnes played gold-digger Vicki Robinson, who temporarily comes between Maureen O'Hara and Brian Keith.

She wrote a weekly book review[14] for the Los Angeles Times,[15] and her column "Touching Home" was carried by the Chicago Tribune and the New York News Syndicate.