Born in St. Louis, Missouri, Nolan first appeared on stage on the showboat Goldenrod when she was 13 months old. She acted on the showboat for 12 years. Her family also acted in tent shows and had their own troupe, the Circle Stock Company. She graduated from high school in St. Louis and sang on a radio station there.
Nolan served for two terms as the first female president of the Screen Actors Guild (1975–79). She also served on SAG's board of directors for a dozen years.
She is a life member of the Actors Studio and a recipient of the Women in Film Crystal Award.
In 1978, U.S. President Jimmy Carter appointed Nolan to the board of the Corporation for Public Broadcasting.
On Broadway, Nolan played Wendy in the original Broadway production of the Styne-Comden-Green musical version of Peter Pan (1954–55), starring Mary Martin and Cyril Ritchard, and she played Amy in Love in E-Flat (1967).
Beyond Broadway, she "did major summer and winter theater ..."
Nolan's television debut came in an episode of The Philco Television Playhouse.
Nolan had the role of Wendy in the first two live telecasts (1955 and 1956) of the musical, but she spent most of her career on television. She had a regular role as the teenaged cousin Liz in the 1953-1954 ABC sitcom Jamie, starring Brandon deWilde in the title role.
Nolan made other appearances over the years on such series as Gunsmoke, The Lloyd Bridges Show, The Untouchables, Breaking Point, Crossing Jordan, Ally McBeal, Chicago Hope, All My Children, Murder, She Wrote (1991) episode "The Prodigal Father", Magnum, P.I. episodes "The Ugliest Dog in Hawaii" (1981) and "Double Jeopardy" (1982), this last one in which Larry Pennell co-guest starred, The Incredible Hulk, Quincy M.E., The Love Boat, Charlie's Angels, The Rockford Files, The Bionic Woman, Kolchak: The Night Stalker, Love, American Style, Bewitched, The Big Valley, The Alfred Hitchcock Hour,Thriller, Burke's Law, Meet McGraw, and Ben Casey.
Nolan appeared with fellow guest star Michael Landon in the 1958 episode "Rose of the Rio Bravo" on the ABC Western series Tombstone Territory, starring Pat Conway and Richard Eastham. She also appeared on the NBC interview program Here's Hollywood.
She played Kate McCoy on The Real McCoys and was in the military sitcom Broadside (both on ABC). In the last season of The Real McCoys (1962–63), Nolan left the series. It was switched from ABC to CBS and moved from Thursday to Sunday evenings opposite Bonanza on NBC. In the revised format, her character of Kate was said to have died.
On February 23, 1961, Nolan was thrown from a horse and injured while making an episode of The Real McCoys. She missed four months of the program and was "in and out of the hospital many times" before returning in the June 15, 1961, episode.
Nolan appeared on McHale's Navy, which resulted in her own spin-off series, Broadside, in which she led a strong cast that included Edward Andrews, Dick Sargent, Sheila James (in her last regular television series role), Lois Roberts, Joan Staley, George Furth, Arnold Stang, and Jimmy Boyd. It had good ratings, but was dropped by Universal Studios after a single season.
In 1980, Nolan was awarded the Women in Film Crystal Award for outstanding women, who through their endurance and the excellence of their work, have helped to expand the role of women within the entertainment industry.
In 1959, she was nominated for an Emmy Award for Best Supporting Actress (Continuing Character) in a Comedy Series for her work in The Real McCoys.
Nolan married Richard Heckenkamp, a "personal manager for celebrities," November 4, 1962. They were divorced May 19, 1965. They had a son, Spencer, born September 19, 1963.